Criminalisticsjj

Chapter 1

IntroductionTo Criminalistics

CHAPTER OVERVIEW Criminali Crimin alisti stics cs is the pro profes fessio sional nal and sci scient entifi ificc discipline dedicated to the recognition, collection, identi ide ntific ficati ation, on, and ind indivi ividual dualiza izatio tion n of phy physic sical al evidence and the application of the natural sciences to th thee ma matt tter erss of la law. w. Fo Fore rens nsic ic sc scie ienc ncee is th thee application of science to the law. Criminalistics is based on divers diversee scient scientific ific disciplin disciplines. es. Criminalis Criminalistics tics draw dr awss up upon on ch chem emis istr try, y, bi biol olog ogy, y, ph phys ysic ics, s, an and d mathematics to relate physical evidence to crime.

CHAPTER OBJECTIVES At the end of this chapter you will be able to do the following: 1. Define the term term evidenc evidence. e. 2. Identify the reasons why physical evidence is important to criminal investigations. 3. Provide practical examples of the application of physical evidence to criminal investigations. 1

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Introduction To Criminalistics

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Physical evidence has the potential to play a critical role in the resolution of a suspected criminal act. This objective is furthered by the though tho ughtfu tful, l, obj object ective ive and tho thorou rough gh app approa roach ch to the inv invest estiga igativ tivee proces process. s. The fou foundat ndation ion of for forens ensic ic sci science ence is the pre preser servat vation ion of physical evidence that will provide reliable information to aid in an investigation. In order to appreciate the importance of forensic science, the basic principles must be understood. These principles include proper identificati ca tion on an and d co coll llect ectio ion n of evi eviden dence ce at a cr crim imee sc scene ene;; kn know owle ledg dgee of th thee bes bestt practices in the field of criminalistics; the importance of firearms, documents, tool marks, impressions, DNA and trace evidence to the field of criminalistics; and crime scene management. Proper crime scene management includes identification, evaluation, collection and preservation of evidence, thorough search practices, and protection of the scene.

A HISTORICAL PERSPECTIVE The origins of forensic science can be traced to the 1800’s. During this era, forensic specialists were self-taught. There were no special schoo sc hools ls,, cou cours rses es or fo form rmal al tr trai aini ning. ng. On Onee of th thee fi firs rstt si signi gnifi fican cantt applications of forensic science occurred in 1888 in London, England. During the late 1880’s, Jack the Ripper had committed several serial murders in London. Doctors were allowed to examine victims of Jack the Ripper for wound patterns. The use of fingerprint evidence in solving crimes today seems routine and unremarkable. During the 1800’s however, fingerprints were the subject of intense scientific research. During the 1880’s it was discovered that fingerprints are unique to an individual and remain unchanged over a lifetime. This discovery led to the identification of offenders in criminal investigations.

The Points of Comparison Method At on onee ti time me ar arou ound nd 19 1900 00,, th ther eree wa wass a system called the anthropometric system that had been invented by a Frenchman, Alphonse Bertillon (1853-1914), consisting of numerous, minute body measurements, such as finger and forearm

lengths.

This

system

was

in

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competition compet ition with finger fingerprint printing ing (techn (technically ically called dactyl dactylography) ography),, discove dis covered red by Henr Henry y Fau Faulds lds and popu popular larize ized d by Fra Franci nciss Gal Galton ton.. Bertillon based his system on the use of 11 points of comparison, calculating his odds of being wrong on any given match being 4 million to 1. These types of calculations form the basis of a number of forensic science sci encess rel relyin ying g upo upon n the Poi Points nts of Com Compar pariso ison n met method, hod, such as odon od onto tolo logy gy,,

fire fi rear arms ms

exam ex amin inat atio ion, n,

and an d

ques qu esti tion oned ed

docu do cume ment nt

examina exam inatio tion. n. Due to popu populat lation ion gro growth wth sin since ce Ber Bertil tillon’ lon’ss tim time, e, the contemporary method is based on at least 12 points of comparison and an odds ratio of about 6 million to 1. An odds ratio or percent chance of o f being wrong also characterizes the quantitative information provided by modern analytical techniques such as spectrography, chromatography, and DNA typing (in the case of DNA, the odds ratio is an amazing 30 billion to 1). Other milestones in the development of criminalistics during the 1800’s were: The first recorded use of questioned document examination. •

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The development of tests for the presence of blood in a forensic context. A bullet comparison used to catch a murderer. Comparison of a bullet and/or expended cartridge case to a known firearm. The first use of toxicology, specifically arsenic detection, in a jury trial. The development of the first crystal test for hemoglobin using hemin crystals. The development of a presumptive test for blood. The first use of photography for the identification of criminals and documentation of evidence and crime scenes. The first recorded use of fingerprints to solve a c rime. Development of the first microscope with a compa rison bridge.

Duri Du ring ng th thee 19 1900 00’s ’s fo fore rens nsic ic sc scie ienc ncee de devel velope oped d in into to a fo form rmal al academicc disci academi discipline. pline. One of the first steps in this progression progression was the establ est ablish ishmen mentt of a for forens ensic ic sci science ence cur curric riculu ulum m in 1902 by Swi Swiss ss Professor R. A. Reiss at the University of Lausanne, Switzerland. This led to the formation of university courses and degrees in criminalistics and police science during the 1930’s. Crimi Criminalist nalistics ics made significant significant

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advances along with the rise in technology during the 1900’s. The following are some of these advances: Establishment of the popular practice of using the comparison microscope for bullet comparison in the 1920’s. •

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Development of the absorption-inhibition ABO blood typing technique in 1931. Invention of the first interference contrast microscope in 1935 by Dutch physicist Frits Zernike (Received Nobel Prize in 1953). Development of the chemiluminescent reagent luminol as a presumptive test for blood.

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Study of voice print identification.

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Invention of the Breathalyzer for field sobriety tests.

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Use of heated headspace sampling technique for collecting arson evidence. Development of the scanning electron microscope with electron dispersive X-ray technology.

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Identification of the polymorphic nature of red blood cells.

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Enactment of the Federal Rules of Evidence (1975).

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Establishment of one of the first academic departments of criminology/criminalistics at the University of California at Berkley (1950). American Academy of Forensic Science (AAFS) was formed in Chicago. Evaluation of the gas chromatrograph and the mass spectrometer for forensic purposes. Development of the polymerase chain reaction (PCR) technique for clinical and forensic applications. Use of DNA to solve a crime and exonerate an innocent suspect (1980). Introduction of DNA and the challenge of certification, accreditation, standardization and quality control guidelines for both DNA Laboratories and the general forensic community (1987).

WHAT IS EVIDENCE? Evidence is defined as information submitted in a legal proceeding that establishes or disproves an alleged set of facts. Evidence is the basis

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of any cr crim imin inal al cha charg rge. e. Wi With thou outt evi evide denc ncee to su suppo pport rt a cha charg rgee of cr crim imin inal al wrongdoing, this allegation would be unable to be proven. The standard of pr proo ooff in a cr crim imin inal al ca case se is th that at an any y al alle lega gati tion on mu must st be pr prov oven en be beyo yond nd a reasonable doubt. This is a very high burden of proof. In a non-criminal case, such as a contract dispute or a small claims action, the standard is much lower. The standard of proof in these cases in based upon a preponderance of the evidence. This means an allegation is more likely true than not true. A prepond preponderance erance of evidence can be trans translated lated to a stan st anda dard rd of pr proo ooff ov over er 50 50%. %. Be Beyo yond nd a re reas ason onab able le do doub ubtt is a mu much ch ha hard rder er standard to meet. In contrast, the beyond a reasonable doubt standard calls for an excess of 90% standard of proof. Evidence collected at a crime scene plays a vital role in any criminal inve in vest stig igat atio ion. n. Th This is ev evid iden ence ce ma may y pr prov ovee th that at a cr crim imee ha hass be been en committed, link a suspect to the scene or victim, establish the identity o f a sus suspect pect or vic victim tim,, cor corrob robora orate te wit witnes nesss acco account unts, s, and exon exonera erate te innocent parties. Evidence gathered at a crime scene also provides leads for investigators investigators to follow up on. Physical evidence is a real, tangib tangible le object presen presentt at the crime scene. Physi Physical cal evidence evidence can can take a variet variety y of forms for ms at a cri crime me sce scene. ne. At the scene of a bur burgla glary ry inv invest estiga igatio tion, n, impressions such as fingerprints, tool marks, foot ware impressions and tire marks are examples of physical evidence that may be collected. Biological, trace, firearm evidence and questioned documents are also examples of physical evidence. Biological evidence includes blood, semen, cellular material, body fluids, hair, nail scrapings, and blood stai st ain n pa patt tter erns ns.. We Weap apons ons,, gu gunp npowd owder er pat patte tern rns, s, car cartr trid idge ge cas cases es,, proje pr ojecti ctiles les,, fra fragme gments nts,, pel pellet lets, s, wadd wadding ing,, met metall allic ic res residu idues, es, and pro projec jectil tilee wounds wou nds or imp impact actss are exam example pless of fir firear earm m evi evidenc dence. e. Que Questi stioned oned document evidence includes handwriting, mechanically produced text, papers, writing implements, inks, and anything upon which a symbol can be placed.

Bioscience in Action: Interesting Cases Rape Ra pe In Inves vestig tigati ation. on. An incapacitated woman claimed she was

raped at a party in Albany, New York. The woman was unable to identify her attacker. Albany City Police secured and submitted blood specimens taken from eight males present at the party. DNA patterns were developed for all eight suspects. The results of the DNA analysis directly implicated one of the eight subjects in the rape.

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Homicide Homi cide Inve Investig stigatio ation. n. An accomplice to a murder told police

investigators that his partner had murdered a man, moved the body from the crime scene in a vehicle and threw the body from a bridge. DNA analysis confirmed this witness’s account of the incident. Investigators found the victim’s blood at the crime scene, in the vehicle used to transport the victim and on three garden tools used in the murder. An examination of the bridge from which the victim was thrown over, reveal rev ealed ed hairs hairs on the rai railin ling. g. Based Based upon thi thiss findi finding, ng, the the exa exact ct sit sitee fro from m which the body was thrown was identified.

THE IMPORTANCE OF PHYSICAL EVIDENCE The value of physical evidence in a criminal investigation cannot be under un derst stat ated ed.. An in indi divi vidu dual’ al’ss gu guil iltt or in innoc nocenc encee can hi hing ngee upo upon n ev evid idenc encee collected at a crime scene. This type of evidence is more reliable than eyewitness accounts of an incident. Over time, people’s memories can fade. There is a tendency of people to fill in parts of an incident that they did not see in its entirety. In contrast to eyewitness testimony, physical evidence eviden ce does not change. A finger fingerprint print taken from a crime scene ten years ago is equally as reliable as if it were collected today. Physical evidence can prove that a criminal act did in fact occur and it can establish key elements of the offense. The crime of rape generally define def ined d is sex sexual ual int interc ercour ourse se aga agains instt the vict victim’ im’ss wil willl or cons consent ent.. Physical Physi cal evidenc evidencee such such as torn clothi clothing ng and and bruis bruising ing of the rape victi victim’s m’s body support the lack of consent c onsent element of this crime. A suspect can be placed in direct contact or in close proximity with thee vi th vict ctim im or cr crim imee sc scen ene. e. In a se sexu xual al as assa saul ultt or ra rape pe ca case se,, a sa samp mple le of th thee suspect’s semen may be collected from the victim’s body. Through the use of DNA analys analysis is this evidence can be used to identify the suspect and place that suspect in contact with the victim. Physical Physic al evidence can establ establish ish the identi identity ty of a suspect or perso person n associated assoc iated with with the crime. crime. At the scene of a burgla burglary, ry, a finger fingerprint print found found at the point of entry can identify as suspect and place that suspect at the scene. A person may be exonerated or eliminated as a suspect in an investigati inves tigation on based upon physi physical cal evidence. Indivi Individuals duals have been released from prison after being ruled out of a crime by DNA analysis. In an int interv erview iew or int interr errogat ogation ion sit situat uation ion,, phys physical ical evi evidenc dencee can pla play y a cri critic tical al rol role. e. In a ban bank k rob robber bery y inv invest estiga igatio tion, n, a sus suspect pect is ide identi ntifie fied d and and

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questio ques tioned ned.. Thi Thiss sus suspec pectt adam adamant antly ly den denies ies bei being ng inv involv olved ed in the robbery. When confronted with a video surveillance tape of the robbery clearly identifying him/her, the suspect confesses to the crime. A vi vict ctim im’s ’s st stat atem ement ent or te test stim imony ony can be co corr rrobo obora rate ted. d. In a dom domes esti ticc violence case, a female victim claims to have been struck numerous times by her partner, causing significant bleeding. The victim’s spouse is later contacted and has blood on his hands and clothing. The suspect claims this blood is his own from an accident at home. Analysis of the blo b lood od on th thee su susp spect ect’s ’s ha hands nds an and d cl clot othe hess de dete term rmin ines es th that at it bel belong ongss to th thee victim, victi m, thereb thereby y corro corroborati borating ng her state statement. ment. Physic Physical al eviden evidence ce may also be used in the alternative, to discredit an untruthful victim. In a burglary bu rglary investigation, the lack of physical evidence, such as no signs of forced entry, may indicate that a victim is being untruthful. This lack of evidence may indicate another criminal act entirely, such as insurance fraud. Figure Figur e 1.1 The Importanc Importance e of Physical Physical Evidence Evidence and the Law

Title: National Conference on Science and the Law Proceedings.

Series: Research Forum Author: National Institute of Justice Published: NIJ, July 2000 Subject: Criminal Justice System Preface

The intersections of science and law occur from crime scene to crime lab to criminal prosecution and defense. Although detectives, forens for ensic ic sci scient entist ists, s, and att attorn orneys eys may have dif differ ferent ent voca vocabul bulari aries es and perspectives, from a cognitive perspective, they share a way of thinking that is essential to scientific knowledge. A good detective, a well-trained forensic analyst, and a seasoned attorney all exhibit “what-if” thinking. This kind of thinking in hypotheticals keeps a detective open-minded: it prevents a detective from ignoring or not collecting data that may result in exculpatory evidence. This kind of thinking in hypotheticals keeps a forensic ana lyst honest: it prevents an analyst from ignoring or downplaying analytical results that may be interpreted as ambiguous or exculpatory evidence. This kind of

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Figure 1.1 The Importa Importance nce of Phys Physical ical Eviden Evidence ce and and the Law (cont (cont.) .)

thinking in hypotheticals keeps attorneys thoroughly prepared: it prevents a prosecutor from ignoring alternative theories of the crime that will surely arise in the defense, and it keeps the defense open to raising alternative theories. Our adversarial system of justice relies on thinking in hypotheticals, examining each possibility, looking at all the angles because we expect proof beyond a reasonable doubt. We have already seen too many times what happens when “what-if” thinking breaks down. Consider what happens when a detective refuses “what if” thinking. Exculpatory evidence is not collected collec ted at the crime scene; an innoce innocent nt person may be convicted. Evidence is collected in such a sloppy manner that it cannot be processed by the crime lab; a guilty gu ilty person may be set free. Consider what happens when a forensic analyst refuses “what if” thinking. A crime lab technique has been accepted for the last 50 years; no one has ques questio tioned ned its vali validit dity y or rel reliab iabili ility ty beca because use ever everyon yonee jus justt belie believes ves tha thatt it wor works; ks; peo people ple may be wro wrongf ngfull ully y conv convict icted ed or exculpated by a scientifically unsound technique that is presented as scient sci entifi ificc evi evidenc dence. e. Or cons conside iderr what happens when “wh “what at if” thinki thi nking ng bre breaks aks dow down n in the cour courtro troom. om. Jud Judges ges nai naivel vely y acce accept pt whatever scientists with a particular set of credentials tell them, the scientist-witness is allowed to represent both the opinions of the entire scientific discipline as well as specific opinions with regard to the case, and the expert witness industry is thriving. Curr Cu rren entl tly, y,

thee th

crim cr imin inal al

just ju stic icee

prof pr ofes essi sion on

hass ha

seve se vera rall

mechanisms for ensuring that “what-if” thinking does not break down. Daubert, and now Kumho, hearings can highlight serious deficiencies in traditionally accepted forensic sciences. Training for judg j udges es an and d la lawy wyer erss can up upgr grad adee th thei eirr ab abil ilit ity y to det deter ermi mine ne th thee val value ue of scientific evidence and to distinguish between good investigative leads, which may result from pre- scientific techniques, and solid scient sci entifi ificc evi evidenc dence, e, whi which ch der derive ivess fr from om the sci scient entifi ificc met method hod.. Resear Res earch ch by acad academi emics cs or sci scient entifi ificc org organi anizat zation ionss suc such h as the National

Acade dem my

of

Sci cien encces

can

provi vide de

ansswers an

to

methodological dilemmas, which face any science moving from the

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Figure Figur e 1.1 The Importa Importance nce of of Physical Physical Evide Evidence nce and and the Law Law (con (cont.) t.)

laboratory to the crime scene. Law enforcement training can provide detectives and departments with best practices for investigation and evidence collection, such as the National Institute of Justice’s recent publication on crime scene investigation. Technical working groups that are discipline based, such as the National Institute of Justice’s Technical Working Group on Eyewitness Evidence, can provide checks on scientific and investigative procedures and interpretation of results. But even wit with h suc such h homo homolog logous ous way wayss of thi thinki nking, ng, jud judici icial al decisions, and educational safeguards in place, science and law continu cont inuee to be unea uneasy sy par partne tners. rs. Ques Questio tions ns abou aboutt thi thiss par partne tnersh rship ip for form m the basis for the following papers, from scientists, attorneys, and judges, which all address, from differing aspects, the relationship between science and law. It is hoped that by facing these questions directly we shall find answers that that enable us to use science science and law in the service of truth and justice. Carole E. Chaski, Ph.D. Executive Director Institute for Linguistic Evidence, Inc. Georgetown, Delaware Source: The entire report can be viewed at: http://www.ncjrs.org/txtfiles1/nij/179630.txt

Figure 1.2 An Introduction Introduction to Criminalistics and and Physical Physical Evidence

A cr crim imin inal alis istt (a (aka ka cr crim imee sc scen enee te techn chnic icia ian, n, ex exam amin iner er,, or investigator) is a person who searches for, collects, and preserves physic physical al evi evidenc dencee in the inv invest estiga igatio tion n of cri crime me and sus suspect pected ed criminals. They typically work in city or regional crime labs and are expected to do more than the forensic scientists and crime lab tech te chni nici cian anss th ther ere. e. Th They ey ar aree ex expe pect cted ed to be on ca call ll 24 ho hour urss a da day y to go out to crime scenes, frankly when and where detectives are stumped. Some jurisdictions require the presence of a criminalist at all major crime scenes. The services of a criminalist are used at the beginning of a cas case. e. By co cont ntra rast st,, th thee se serv rvic ices es of a fo fore rens nsic ic sc scie ient ntis istt ar aree pr prim imar aril ily y

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Figure 1.2 An Introduct Introduction ion to Criminal Criminalistic isticss and Physica Physicall Evidence Evidence (cont (cont.) .)

used us ed at th thee en end, d, or co cour urtr troo oom m te test stim imon ony y ph phas ase, e, of a cas casee. Al Alll cr crim imee la lab b empl em ploy oyee eess mu must st be re read ady y to of offe ferr ex exper pertt te test stim imony ony in co cour urt, t, ho howe wever ver.. Crim Cr imin inal alis ists ts us usua uall lly y ge gett ca call lled ed to te test stif ify y ab abou outt ma matt tter erss of contamination, cross-contamination, and chain of custody, b ut many of th them em (s (seni enior or cr crim imin inal alis ists ts)) ha have ve dev devel elop oped ed an in inte terp rpre reti tive ve expertise, for example, in blood spatter analysis, trace evidence, impression evidence, or drug identification, as well as skills at crime reconstruction and sometimes profiling (Levinson & Almog 1989). The term criminalistics ( Kriminalistik ) was first used by Hans Gross in 1891, but the term was mostly forgotten until the 1960s when a series of cooperative movements took place between police agenci age ncies es and cri crimin minal al jus justic ticee or cri crimin minolo ology gy depa departm rtment entss to est establ ablish ish crimin cri minali alisti stics cs (Un (Unive iversi rsity ty of Cal Califo iforni rnia, a, Ber Berkel keley) ey) and for forens ensic ic science (Michigan State) college programs. Professors Paul Kirk in California and Ralph Turner in Michigan (among many others) were pioneers in those movements. As Osterburg and Ward (2000) imply, criminalistics programs followed the police science model to record, identi ide ntify, fy, and int interp erpret ret the minutia (mi (minut nutee det detail ails) s) of phys physical ical evid ev iden ence, ce, an and d fo fore rens nsic ic sc scie ience nce fo foll llow owed ed th thee me medi dica call sc scie ienc ncee mo model del to apply generally accepted principles of established disciplines (like pathology, serology, toxicology, odontology, and psychiatry) to the scientific examination of physical evidence. Forensic science is the broader term because criminalistics is a branch of forensic science. “Forensic” is simply an adjective that can be put in front of any scie sc ience nce ap appl plie ied d to ans answe weri ring ng le lega gall que quest stio ions ns.. Th Thee Am Amer eric ican an Academy of Forensic Sciences web site highlights about twenty various degree programs that relate to some aspect of criminalistics or forensic science education. The world’s first crime labor laboratory atory was estab establishe lished d by Edmond Locard in Lyon, France during 1910. The famous Locard Exchange Principle that “every contact leaves a trace” is named for him, after Locard solved a strangling case by using fingernail scrapings. In America, a few major cities and the FBI obtained crime labs during the 1930s, and by the mid-1970’s (the birth of criminal justice), 47 states had crime labs. A few criminal justice programs that existed

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Figure Figur e 1.2 An Introduc Introduction tion to Crimina Criminalistic listicss and Physica Physicall Evidence Evidence (cont (cont.) .)

prior to the explosion of the field in 1974 offered a criminalistics or forens for ensic ic sci science ence conc concent entrat ration ion,, but tod today, ay, mos mostt cri crimin minal al jus justic ticee programs only have one course in criminal investigation. Post-1975, the criminal justice model became an attempt to make sense of whole systems of justice, and the criminology model, dominated heavily by soci so ciol olog ogy y un unti till ab abou outt 19 1990 90,, be beca came me th theo eory ry,, re rese sear arch ch,, an and d policy-driven. Many criminalists consider themselves (professional) crim cr imin inol olog ogis ists ts,,

but

few fe w

crim cr imin inol ologi ogist stss

cons co nsid ider er

them th emse selv lves es

criminalists. THE IMPORTANCE OF CRIME LABS

With federal police agencies, two (2) organizations stand out above the rest, the FBI and ATF, mainly because their crime labs are pre prett tty y mu much ch co cons nsid ider ered ed th thee to tops ps in th thee fi fiel eld d and a mo model del fo for r elsewhere. The FBI laboratory has 4 sections: (1) Scientific analysis (DNA, Firearms-to Firear ms-toolmar olmarks, ks, Hairs and Fibers Fibers,, Mater Materials ials Analys Analysis, is, Chemis Chemistry try and Toxicology, Questioned Documents; (2) Special Projects (film, photography, composites, art, computer design); (3) Fingerprinting (some (so me 200 mil millio lion n rec record ords); s); (4) Inv Invest estiga igativ tivee Operati Operations ons and Sup Suppor portt (gre (g rew w out of Qu Ques esti tion oned ed Do Docu cume ment ntss uni unitt an and d in incl clud udes es li liee det detect ectio ion n of variou var iouss sor sorts) ts).. The FBI lab onl only y han handle dless vio violen lentt cri crime, me, wor works ks exclusively for the prosecution, and is considered co nsidered the world’s largest lab. The ATF laboratory handles (1) Explosives, bombs, arsons (and does it well); (2) Trace evidence and deciphering firearms ownership and usage; (3) Disaster response teams (kind of like FEMA); (4) Field support; and (5) some Gang intelligence record keeping. ATF labs are typically very high-tech and have always been accredited. It’s typical for a Crime Lab to have 4 divisions under a Director’s Office: (1) a section dealing with anything pertaining to fluids, this being called called a Serol Serology ogy Division; Division; (2) a secti section on dealing with with unknown substances, drugs, or poisons, this being called a Chemistry or Toxicology Toxicol ogy Division; (3) a secti section on dealin dealing g with anything so small small,, like hairs hairs or fibers, that that they need to be looked at under a micro microscope, scope,

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this th is be bein ing g ca call lled ed a Tr Trac acee Ev Evid iden ence, ce, Bi Biol olog ogy, y, or Mi Micr cros osco copy py Di Divi visi sion on;; and (4) a section dealing with guns, weapons, instrumentation, or whatever, this being called a Ballistics, Firearms, or Fingerprinting (Dusting and Lifting) Division (where Interns usually work). There are about 350 crime laboratories in the U.S. and at least 80% of them are affiliated with a police agency (where they typically hold bureau status in the organization). The rest are located in the private sector and some of these are exemplary and known for a particular specialty: Cellmark Diagnostics (for DNA), Battelle Corp. (for arson cases), and Sirchie Corp. (for fingerprinting and trace evidence collection), to name a few. There is a shortage of DNA laboratories since only 120 labs are set up to do DNA testing (Steadman 2002). Almost all labs in existence are forensic labs, where whe re “fo “foren rensic sic”” mea means ns the exp expert ertss the there re are avai availab lable le to giv givee courtr cou rtroom oom opi opinio nions, ns, but whe when n a lab is set up to rec receiv eivee evi evidenc dencee fro from m ongoing criminal investigations, this is called casework, and the lab is referred to as a casework lab. You can’t just start up a crime lab anywhere or anytime you feel like it. Things are set up geographically so that on average, a lab is almost always 50 miles within 90% of the police agencies. There are some places that buck this pattern, but usually each state has one “parent” lab and 5-6 regional labs. They are always hiring and looking for help, as there’s a labor shortage of qualified applicants. There’ss also There’ also usually usually a work backlo backlog, g, and some labs and and state syste systems ms are so backed up, that it takes many months to get the results back on an evidence analysis. But in all fairness, the backlog situation should not be a concern because crime labs were never intended to replace a field investigation. The point of this is that police investigators shoul sh ould d nev never er co come me to rely on a cr criime lab ab,, bu butt us usee it as a sup uppl plem emen entt to their own investigative skills. Criminalistics and forensic science are not silver bullets.

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THE PROBLEMS OF CRIME LABS

Chain of Custody There are many sources of error. Evidence has to be discovered (police or criminalist), it has to be collected (police, crime scene technician, or criminalist), and then it has to be packaged, labeled, and transported (police supervisor or criminalist). c riminalist). Once it gets to the lab, it has to be logged in, assigned an identification number, placed in sto storag rage, e, kept fro from m int interm erming inglin ling g wit with h oth other er evi eviden dence, ce, and anal analyze yzed d (criminalist, crime lab technician, or o r forensic scientist). Before any laboratory work is done, it must be ensured that the workplace is clean and contamination free. Then, the evidence is visually inspected and properly described to do cument its condition. Often, it will be photographed, weighed, and sketched. Then, the laboratory labora tory worker (crim (criminali inalist, st, crime lab technic technician, ian, or foren forensic sic scient sci entist ist)) wil willl have to fig figure ure out what tes tests ts are app approp ropria riate, te, if sufficient amounts of the evidence exist, prope rly dissect the portion to be tested, and properly prepare the testing material (which might includee the delicate mixing of numerous chemical compounds), all includ the while continuing to document each step. Only then does any testing begin. Some tests include as many as five or six separate procedures, each of which must be properly performed and documented, the eviden evi dence ce pr prop oper erly ly re repa packa ckaged ged and re rela labe bele led, d, and onc oncee aga again in transported to storage. Only then does the lab worker engage in the proces pr ocesss of int interp erpret reting ing what what the expe experim riment entss have have dis disclo closed sed.. A rep report ort is prepared and the contents of that report must be precisely correct. At th thee pr pros osec ecut utor’ or’ss di disc scre reti tion, on, th thee ev evid idenc encee ha hass to ma make ke it bac back k to the police evidence room, where it will be stored until he/she decides they want to use it or want more testing performed, in which case it goes back to the crime lab. It should be fairly evident that all this transportation of evidence gives rise to numerous possibilities for error in the form of destruction, mishandling, and contamination.

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Integrity It’s important a crime lab find some system for establishing its credentials as a forensic laboratory. A couple of the organizations that perform this function include the American Society of Crime Labora Lab orator tory y Dir Directo ectors rs (AS (ASCLD CLD), ), the Nat Nation ional al For Forens ensic ic Sci Science ence Tech Te chnol nology ogy Ce Cent nter er (N (NSF SFTC TC), ), an and d th thee Col Colle lege ge of Am Amer eric ican an Pathologists (CAP). In addition, labs that specialize may also apply for credentials from an organization, or Board, which regulates that specialty. For example a lab that performs odontological work might apply to the National Board of Forensic Odontology. Generally, General ly, whenever whenever a lab applies applies for accreditati accreditation, on, it has to meet certain minimum requirements, which include, among other things, the development and publication of: A Qu Qual alit ity y Co Cont ntro roll Ma Manua nuall - Qualit Qualityy control ref refers ers to meas me asur ures es th that at ar aree ta taken ken to en ensu sure re th that at th thee pr produ oduct ct,, fo for r example a DNA-typing result and its interpretation, meets a specified standard of quality. •

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A Quality Assurance Manual - Quality assurance refers to measures that are taken by a laboratory to monitor, verify, and document its performance. A basic business principle is that QA serves as a check on QC . A Lab Testing Protocol - Protocols consist of a few hundred pages of highly techni technical cal manuals and shoul should d includ includee such things as “validation studies” which the lab performed itself to make it capable of performing tests in any particular discipline. A pro progra gram m for pro profic ficien iency cy tes testin ting g - Pro Profic ficien iency cy tes testin ting g dete de term rmin ines es if th thee la lab b wo work rker erss in indi divi vidu dual ally ly,, an and d th thee labo la bora rato tori ries es as in inst stit itut utio ions ns,, ar aree pe perf rfor ormi ming ng up to th thee standards of the profession. In these tests, samples to be examined are given to a laboratory or particular worker, but a test giver already knows the results. There are two methods employed in administering these tests, blind and known. In thee bl th blin ind d te test st,, th thee la lab b wo work rker er do does esn’ n’tt kn know ow th that at a te test st is ta taki king ng place; they think the evidence sample they are working on is just another case. The open proficiency test is like an open

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boo book k ex exam am.. In ad addi diti tion on,, in indi divi vidu dual al la lab b wo work rker erss jo join in associations to beef up their resumes. The two main ones are the American Academy of Forensic Sciences (AAFS), the American Board of Criminalistics (ABC). In gen gener eral al,, at atta tacks cks on la labo bora rato tory ry ex exper perti tise se com comee in th thre reee categories (which are the same techniques for attacking physical evidence): Tampering - Tampering refers to allegations that the crime scene or piece of evidence was tampered with. There’s a presumption of regularity on the side of the prosecution, so this is hard to prove. •

•

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Contamination - Contamination is somewhat easier to allege, given irregularities in the chain of custody. Substitution - Substitution (or mistake) is a problem if the lab worker wor kerss are new new,, ine inexper xperien ienced, ced, or lac lack k the app approp ropria riate te credentials. THE BASICS OF PHYSICAL EVIDENCE

Physical evidence is part of the “holy trinity” for solving crimes — physical evidence, witnesses, and confessions. Without one of the first two, there is little chance of even finding a suspect. In homicide and sex sexual ual ass assaul aultt cas cases, es, physical physical evi evidenc dencee is the num number ber one determinant of guilt or innocence. Physical evidence is also the number one provider of extraordinary clearances, where police can link different offenses at different times and places with the same offender. Working with physical evidence means being aware at all times of what the prosecutor needs to win the case in court. This means knowing the Types of Evidence and the Laws of Evidence. Four Types of Evidence: Testimonial

This Th is is th thee ki kind nd of evi evide dence nce th that at co come mess to co cour urtt th thro roug ugh h wi witn tnes esse sess speaking speaki ng under oath or affir affirmatio mation. n. They could be testi testifying fying about something they saw (eyewitnesses), something they heard (hearsay witnesses), or something they know (character, habit, or custom witnesses).

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Physical

These are tangible objects that are real (sometimes said to speak for themselves because they can be taken into the jury room), direct (no preliminary facts needed), and not circumstantial (do not require an inf infere erence nce to be mad made), e), alt althou hough gh cir circum cumsta stanti ntial al evi eviden dence ce is sometimes offered and strengthened by expert testimony. Examples of phy physi sica call evi eviden dence ce wo woul uld d in incl clud udee th thee gu gun n us used ed to co comm mmit it th thee cr crim ime, e, trac tr acee pa part rtic icle less fo foun und d at th thee cr crim imee sc scen ene, e, pr prope opert rty y re recov cover ered ed,, fingerprints, shoeprints, handwriting, etc. Documentary

This is usually any kind of writing, sound or video recording. It may be the transcript of a telephone intercept. Authentication of the evidence is usually required along with expert e xpert testimony at times. Demonstrative

These The se ar aree ty type pess of re real al ev evid iden ence ce us used ed to il illu lust stra rate te,, dem demons onstr trat ate, e, or recreate a tangible thing, for example, a cardboard model mockup of the crime scene or other constructed-to-scale models. The purpose of this stuff to replace timely, expensive, and possibly prejudicial jury trips to the crime scene. Both forensic scientists and criminalists need to be intimately familiar with the Standards of Admissibility for Scientific Expe rtise, sinc si ncee th thes esee var vary y fr from om st stat atee to st stat ate, e, and so some meti time mess even fr from om co cour urtt to court within states. Relevancy test (FRE 401, 402, 403) - this is embodied in the Federa Fed erall Rul Rules es of Evi Evidenc dencee and sta state te ver versio sions ns whi which ch ess essent ential ially ly involve a liberal rule allowing anything that materially assists the trie tr ierr of fa fact ct (j (jur ury) y) an and d is de deem emed ed re rele levan vantt by th thee tr trie ierr of la law w (j (jud udge ge). ). Frye Standard ( Frye v. U.S. 1923)

For the results of a scientific technique to be admissible, the technique must be sufficiently established to have gained general acceptance accepta nce in its parti particular cular field field.. This This is the “genera “generall accepta acceptance” nce” test that often requires knowledge of the literature.

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Coppolino ino v. State 1968) Coppoli Cop polino no Stan Standard dard ( Coppol

Thee cou Th court rt al allo lows ws a nov novel el te test st or pi piece ece of ne new, w, so some meti time mess controversial, science on a particular problem at hand if an adequate foundation can be laid even eve n if the profession as a whole isn’t familiar with it. Marx Standard ( People v. Marx 1975)

The court is satisfied that it did not have to sacrifice its common sense in understanding and evaluating the scientific expertise put before it. This is the “common sense” or “no scientific jargon” test, and it is rarely used Daubert standard (see Lec ture on Daubert). This test requires special pretrial hearings for scientific evidence and speciall proced specia procedures ures on discov discovery. ery. This is a rather stringent stringent test that requires knowledge of Type I and Type II error rates, as well as validity and reliability coefficients. CONCEPTS AND PRINCIPLES OF PHYSICAL EVIDENCE

Sinc Si ncee cr crim imin inal alis isti tics cs is th thee re reco cord rdin ing, g, id ident entif ific icat atio ion, n, and interpretat inter pretation ion of minutia (minute details), a number of standard techniques and procedures have been developed to do this. It is important to understand the basic concepts behind these techniques. A more useful term than minutia is striations, which are scratch marks caused by irregularities or lack of microfine smoothness, such as those found on fingerprints, bullets, cartridges, casings, or tool marks. With evidence like paint, hair, grease, and glass, the chemical composition (qualitative and quantitative) provides the details. With other types of evidence, such as glass fragments, the morphology (or form) of an object reveals valuable information, such as a jigsaw puzzle fit linking fit linking pieces of broken glass together. Crimin Cri minali alists sts know how to oper operate ate a var variet iety y of dev device icess and machi ma chines nes.. Th Thee th thre reee si simp mple lest st dev devic ices es ar aree li light ghts, s, cam camer era, a, and microscope. By adjusting the light on an object, the morphological and composition characteristics of evidence often become visible. A basic principle is contrast, as in when the background color of an object is made different than the foreground color. Cameras often allow the use of lens filters to screen out certain colors, and contrast

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(among other things) can be increased or decreased in photography. Micros Mic roscope copess are the mai main n tec techni hnique que for enl enlarg arging ing res resolu olutio tion, n, although it is possible to enlarge without enhancing resolution. Most physical evidence reveals valuable detail at magnifications between 2x and 10x 10x.. Th Thee mo more re com compl plex ex de devi vice cess ar aree ca call lled ed an anal alyt ytic ical al instruments, and consist of the following: Table 1 Analytical Instrument

Instrument

Substance

Effect of Sample

Information

Spec Sp ectr trop opho hoto tome mete ters rs

Orga Or gani nic/ c/In Inor orga gani nicc

Nond No ndes estr truc ucti tive ve

Quan Qu anti tita tati tive ve

Mass spectrography

Organic

Destructive

Qualitative

X-Ray Diffusion

Crystalline

Nondestructive

Qualitative

Neuutr Ne tron on Act ctiv ivat atio ionn

Inor In org gan anic ic

Nond No ndes estr truc ucti tivve

Qua uali lita tati tivve/ e/Q Qua uant ntiita tati tivve

Scan Sc anni ning ng El Elec ectr tron on

Orga Or gani nic/ c/In Inor orga gani nicc

Nond No ndes estr truc ucti tive ve

Semi Se mi-q -qua uant ntit itat ativ ivee

X-Ray Dispersion

Inorganic

Nondestructive

Qualitative

Chromatography

Organic

Nondestructive

Qualitative/Quantitative

There The re ar aree ma many ny mo more re or organ ganic ic su subs bsta tance ncess th than an in inor orga gani nicc substances. Most drugs, explosives, hairs, and biological fluids are organ or ganic ic,, bas based ed on th thee el elem ement ent car carbon bon.. Mo Most st di dirt rt,, gu gunpo npowd wder er,, po pois ison ons, s, paint, and glass are inorganic, although some substances represent a mix or organic and inorganic. Without doubt, the most important concept in criminalistics is identi ide ntific ficati ation, on, or what Paul Kir Kirk k cal called led individualization (Kirk 1936). Identification produces unequivocal (certain) interpretation. An equivocal crime scene, by comparison, yields physical evidence subj su bject ect to di diff ffer eren entt in inte terp rpre reta tati tion on (a (and nd is th thee bas basis is fo forr cr crim imee reconstruction and profiling). When a number of details are put together togeth er (as in points of compari comparison), son), so that they they constitut constitutee a class of of one (by itself), they are said to establish an identity, also called individual characteristics, or entities in a class by itself. At th this is po poin int, t, if there are similarities between evidence from the crime scene and evidence from a suspect, the expert can say, without a doubt, that identity has been individualized.

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It is important to clearly understand the concepts of identity, match, mat ch, cla class ss and ind indivi ividual dual cha charac racter terist istics ics.. Ide Identi ntity ty is a set of characterist charact eristics ics (combi (combination nationss of class charact characterist eristics ics or combin combinations ations of cl clas asss an and d in indi divi vidu dual al ch char arac acte teri rist stic ics) s) by wh whic ich h a th thin ing g is recognizable or known. Identity is the same as pattern. pattern. A pattern is established, establ ished, for example, when a parti particular cular piece of class evidence evidence like li ke fi fibe berr (f (for or wh whic ich h th ther eree ar aree la larg rgee qu quant antit itie iess in th thee po popu pula lati tion) on) is put together with another piece of class evidence like red hair (which usua us uall lly y onl only y ex exis ists ts in th thee su subp bpop opul ulat atio ion n of wh whit itee peo peopl ple) e).. It ca canno nnott be said the investigator has “individualized” anything at this point, but thee re th red d hai hairr in th this is ex exam ampl plee ca can n be co cons nsid ider ered ed eno enoug ugh h of an in indi divi vidu dual al charact char acteri eristi stic, c, whi which ch com combin bines es wit with h the cla class ss cha charac racter terist istic ic to establish identity. At this point, if there is a “match” between the fibers and hair from the crime scene with a suspect, the examiner can say the crime scene (unknown or questioned) sample “may have come from the same source” as the suspec suspect’s t’s (known or exempl exemplar) ar) sample, which is sufficient for probable cause. Identity can also be used to conclusively eliminate people as suspects. Class characteristics alone do not allow matches with a single suspect. Matches for evidence with individual characteristics do allow all ow pin pinpoi pointi nting ng a par partic ticula ularr sus suspect pect.. Matches at the individual level are called similarities, because in theory, there’s no such thing as a perfectt match perfec match.. An example of a similarity, or match in individual chara cha ract cter eris isti tics cs,, wo woul uld d be a nu numb mber er of com compa para rabl blee poi point ntss of comparison between the friction ridge lines on a latent (crime scene) fingerprint with the fingerprints of a particular suspect. This kind of (true) match allows the examiner to say that, beca use the similarities outwe out weig igh h an any y di diss ssim imil ilar arit itie ies, s, th thee cr crim imee sc scen enee (u (unkn nknow own n or quest que stio ione ned) d) sa samp mple le “di “did d com comee fr from om th thee sa same me so sour urce ce”” as th thee su susp spec ect’ t’ss (known or exemplar) sample, which is sufficient, most of time, for proof beyond a reasonable doubt. Reli Re liabi abili lity ty and in inte tegr grit ity y ar aree en enhan hance ced d if th thee exa exami miner ner has conduct cond ucted ed tes tests ts on sta standar ndards ds usi using ng con contro trols. ls. A st stan anda dard rd is th thee opposite of exemplar. exemplar. An exemplar always comes from a suspect or someth som ething ing rep repres resent enting ing a know known n mod modus us ope operan randi di or sig signat nature ure..

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Standards consist of simultaneous tests done on items taken from the “background” or nearby the crime scene (control sample), items similar to one the suspect used, such as test firings of a similar weapon (standard sample), or items used for calibration purposes kept in stock at the lab (reference sample). The astute student may notice that the word “match” is used a couple of diff different erent ways in criminalistics criminalistics.. Nobody uses the phras phrasee (true) match, for example, like I have used in my explanations above. Some people prefer the term “matching” (Ramsland 2001). Abuse of the term “match” is even worse in forensic science, which allows different disciplines to set their own criteria and standards. To wrap things up, let’s conclude with an interesting topic, the points of comparison method, and then attempt to present a table, which classifies evidence by their class and individual characteristics. THE POINTS OF COMPARISON METHOD

At on onee ti time me ar arou ound nd 19 1900 00,, th ther eree wa wass a sy syst stem em ca call lled ed th thee anthropometric system that had been invented by a Frenchman, Alphonse Bertillon (1853-1914), consisting of numerous, minute body measurements, such as finger and an d forearm lengths. This system wass wa

in co comp mpet etit itio ion n

with wi th fi fing nger erpr prin inti ting ng

(tec (t echn hnic ical ally ly

call ca lled ed

dactylography), discovered by Henry Faulds and popularized by Francis Galton. Bertillon based his system on the use of 11 points of comparison, calculating his odds of being wrong on any given match being 4 million to 1. These type of calculations calculations form the basis of a number of forensic sciences relying upon the Points of Comparison method, such as odontology, firearms examination, and questioned document examination. Due to population growth since Bertillon’s time, the contemporary method is based on at least 12 points of comp co mpar aris ison on and an odd oddss ra rati tio o of of ab abou outt 6 mi mill llio ion n to to 1. An od odds ds ra rati tio o or or percent chance of being wrong also characterizes the quantitative inform inf ormati ation on pro provid vided ed by mod modern ern anal analyti ytical cal tech techniq niques ues suc such h as spectrography, chromatography, and DNA typing (in the case of DNA, the odds ratio is an amazing 30 billion to 1).

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There is no such thing as a comprehensive classification scheme for all types of physical evidence. Some types of class evidence can be somewhat individualized, such as hair and blood, and some indivi ind ividua duall typ types es are bes bestt con consid sidere ered d bot both h cla class ss and ind indivi ividual dual eviden evi dence ce.. Wi With th th that at ha havi ving ng bee been n sa said id,, he here re’s ’s a ta tabl blee th that at la lays ys ou outt so some me basic distinctions: Class Evidence

Individual Evidence

Drugs

Fingerprints

Fibers

Toolmarks

Hair

Handwriting

Blood

DNA

Glass

Firearms

Soil

Shoeprints

Source: http://faculty.ncwc.edu/to http://faculty.ncwc.edu/toconnor/315/315lect0 connor/315/315lect02.htm 2.htm

SUMMARY Modern Mod ern day cri crimin minali alisti stics cs has has adva advanced nced alo along ng wit with h tec technol hnology ogy fro from m itss or it orig igin inss in th thee 180 1800’ 0’s. s. Th Thee th thor orou ough, gh, th thoug ought htfu full co coll llec ecti tion on of ev evid idenc encee at a crime scene forms the foundation of a criminal investigation. The importance of physical evidence cannot be underemphasized. This evidence tells the story of a criminal offense. Physical evidence can pro rovi vide de wh who, o, wh what at,, wh when en,, wh wher eree an and d so some meti time mess wh why y in th thee re reso solu luti tion on of a criminal case.

DISCUSSION QUESTIONS 1. What are three examples of advances in in criminalistics during the 1900’s? 2. Provide at least three examples of the application of physical evidence in a criminal case. 3 Why is physical evidence important important in solving crimes?

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ADDITIONAL READINGS Handbook of Forensic Services, United States Department of Justice, Federal Bureau of Investigation: 1999 www.fbi.gov. Advancing Justice through DNA Technology, Office of the President, http://www. ojp. usdoj. gov March 2003 Crime Scene Investigation, Office of Justice Programs, National Institute of Justice, World Wide Web Site http;//www. ojp. usdoj.gov, 1999 An Introduction to Criminalistics and Physical Evidence; Tom O’Conner Ph.D. North Carolina Wesleyan University http://faculty.ncwc.edu

Criminalisticsjj

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