Forensic Science An Introduction

What is forensic science? Science applied to the law or in a legal arena Science applied to the law or in a legal arena “…the application of science to those criminal and civil laws that are enforced by police agencies in the criminal justice system.” Saferstein “…the application of science to those criminal and civil laws that are enforced by police agencies in the criminal justice system.” Saferstein

What is a key concept in FS? Locard’s Exchange Principle (~1910) Locard’s Exchange Principle (~1910) Whenever a criminal comes in contact with a person or object there is a cross-transfer of evidence. Whenever a criminal comes in contact with a person or object there is a cross-transfer of evidence.

What are the consequences of Locard’s Exchange Principle? The perpetrator leaves evidence behind and also takes evidence away The longer you wait before collecting evidence the less there is left Every person at the crime scene including police investigators will contaminate it

Realistic?

What is Forensic Science Trying to Do? The goal of Forensic Chemistry is to determine the provenance of a sample. The goal of Forensic Chemistry is to determine the provenance of a sample. Link it to a person, place or thing Link it to a person, place or thing prov·e·nance Pronunciation: 'präv-n&n(t)s, 'prä-v&-"nän(t)s Function: noun Etymology: French, from provenir to come forth, originate, from Latin provenire, from pro- forth + venire to come -- more at PRO-, COME 1 : ORIGIN, SOURCE 2 : the history of ownership of a valued object or work of art or literature PRO-COMEORIGINSOURCEPRO-COMEORIGINSOURCE

The Crime Lab Psychiatrist Odontologist EntomologistAnthropologist Pathologist Engineer

Crime lab organization Departments in the crime lab Departments in the crime lab Biological evidence- examples? Biological evidence- examples? Trace evidence- examples? Trace evidence- examples? Document examination Document examination Photographs Photographs Computer technology evidence Computer technology evidence Ballistics and firearms Ballistics and firearms Others? Others?

Anthrax Letters What types of evidence would you look for? 5 dead 17 sickened

Anthrax Letters Trace hair and fibers in envelope Trace hair and fibers in envelope Ink analysis may reveal manufacturer Ink analysis may reveal manufacturer DNA from stamp or envelope seal DNA from stamp or envelope seal Cellophane tape ends match over four letters Cellophane tape ends match over four letters Paper examination may identify manufacturer Paper examination may identify manufacturer Fingerprints Fingerprints Photocopier toner may reveal manufacturer Photocopier toner may reveal manufacturer Handwriting analysis shows four letters written by same person Handwriting analysis shows four letters written by same person Indented writing Indented writing Bar codes for mail handling Bar codes for mail handling

Analytic vs. Forensic Chemistry Similarities Analytic Wants to find composition of samples Wants to find composition of samples Compounds Compounds Proportions in mixtures Proportions in mixtures Uses same instruments as forensic Uses same instruments as forensic Forensic Wants to find composition of samples Compounds Proportions in mixtures Uses same instruments as analytical

Analytic vs. Forensic Chemistry Differences Analytic Known source Known source Good idea of what the composition is likely to be Good idea of what the composition is likely to be Used for quality control Used for quality control Well defined samples and controls Well defined samples and controls Forensic Need to determine source Little knowledge of composition Often complex mixtures so hard to find appropriate controls

Roles of the Forensic Scientist Analyze physical evidence Analyze physical evidence Provide expert testimony Provide expert testimony Train evidence collection units in recognition, collection and preservation of evidence Train evidence collection units in recognition, collection and preservation of evidence

The Expert Witness An expert witness can testify as to his/her opinion of what the evidence indicates An expert witness can testify as to his/her opinion of what the evidence indicates A lay witness can only testify as to fact A lay witness can only testify as to fact

The Expert Witness Trial judge must be satisfied that the expert Trial judge must be satisfied that the expert Has skill or knowledge that will aid the court in determining the truth Has skill or knowledge that will aid the court in determining the truth Education (degrees, courses) Education (degrees, courses) Training (internship under experienced practitioner) Training (internship under experienced practitioner) Experience (years on the job, publications, professional societies) Experience (years on the job, publications, professional societies) Trial judge is the gatekeeper Trial judge is the gatekeeper

The Expert Witness Jury assigns weight to the expert’s opinions Jury assigns weight to the expert’s opinions Jury looks at Jury looks at Credentials Credentials Demeanor Demeanor Whether material is presented simply and clearly Whether material is presented simply and clearly Jury is the trier of fact Jury is the trier of fact

A Big Driver in the Plot Can the evidence be admitted into court? Can the evidence be admitted into court?

Admissibility: A Moving Target Frye v. US (1923) Frye v. US (1923) Scientific evidence is admissible only if it has gained general acceptance in the field Scientific evidence is admissible only if it has gained general acceptance in the field Rejected polygraph opinions Rejected polygraph opinions Historical Perspective Historical Perspective Tennessee v. John Scopes (1925) Tennessee v. John Scopes (1925) The Monkey Trial The Monkey Trial

Admissibility: A Moving Target Federal Rule of Evidence 702 (1975) Federal Rule of Evidence 702 (1975) Approved by Congress Approved by Congress More flexible general relevance test for admissibility of opinion testimony by experts More flexible general relevance test for admissibility of opinion testimony by experts “If scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact at issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.” “If scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact at issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.”

Admissibility: A Moving Target Daubert v. Merrell Dow Pharmaceuticals (1993) Daubert v. Merrell Dow Pharmaceuticals (1993) When expert evidence based on “scientific knowledge” is offered at trial, the judge acts as gatekeeper to determine if the evidence is “reliable” When expert evidence based on “scientific knowledge” is offered at trial, the judge acts as gatekeeper to determine if the evidence is “reliable” Four suggested factors in determining reliability Four suggested factors in determining reliability Testable using the scientific method Testable using the scientific method Peer reviewed Peer reviewed Error rates Error rates Acceptability to the scientific community Acceptability to the scientific community Trial judge given lots of flexibility Trial judge given lots of flexibility Muddy waters—what is scientific knowledge? Muddy waters—what is scientific knowledge? What about other types of experts? What about other types of experts?

Admissibility: A Moving Target Why Daubert won on appeal Why Daubert won on appeal When Congress passed Rule 702 it ignored the Frye general acceptability criterion When Congress passed Rule 702 it ignored the Frye general acceptability criterion Frye was no longer “good law”-- Frye was no longer “good law”--

Admissibility: A Moving Target Kumho Tire Co v. Carmichael (1999) Kumho Tire Co v. Carmichael (1999) Daubert factors are extended to non-scientist expert witnesses. Daubert factors are extended to non-scientist expert witnesses. Daubert factors are not the only ones that can be considered Daubert factors are not the only ones that can be considered Trial judge now has enormous flexibility Trial judge now has enormous flexibility

And it’s not settled yet….. Daubert and Kumho apply to federal cases only Daubert and Kumho apply to federal cases only 18 State Courts have adopted Daubert standards 18 State Courts have adopted Daubert standards Other State Courts have rejected Daubert and still use a modified Frye standard Other State Courts have rejected Daubert and still use a modified Frye standard

What’s driving the growth of FS? Miranda decision Miranda decision Fewer confessions Fewer confessions Increase in drug seizures and arrests Increase in drug seizures and arrests More testing More testing DNA profiling DNA profiling More testing with sophisticated equipment More testing with sophisticated equipment Other new technologies Other new technologies

Miranda vs. Arizona (1966) Before questioning by the police, suspects must be informed that they have: Before questioning by the police, suspects must be informed that they have: The right to remain silent The right to remain silent The right to consult an attorney The right to consult an attorney If indigent an attorney will be provided for them If indigent an attorney will be provided for them Anything they say may be used against them in court Anything they say may be used against them in court Arizona Department of Library Archives and Public Records)

Dickerson Dickerson vs US (2000) Dickerson vs US (2000) Congress passed law in 1968 saying voluntary confessions are exempt from Miranda Congress passed law in 1968 saying voluntary confessions are exempt from Miranda Supreme Court overrules Congress in 2000 Supreme Court overrules Congress in 2000 Congress can’t overrule the Supreme Court on constitutionally guaranteed rights except by the amendment process Congress can’t overrule the Supreme Court on constitutionally guaranteed rights except by the amendment process

Results of Miranda Confessions are less likely to hold up in court since the burden of proof of Miranda statement lies on police Confessions are less likely to hold up in court since the burden of proof of Miranda statement lies on police Police and prosecutors rely more independent (scientific) evidence to prove guilt Police and prosecutors rely more independent (scientific) evidence to prove guilt

What is the most common task a forensic scientist performs? Take 5 minutes and discuss this in groups of 4 and then be ready to report out your reasoning. Take 5 minutes and discuss this in groups of 4 and then be ready to report out your reasoning.

Crime Wave or Better Enforcement?

Federal Drug Seizures

Arrests by Drug Type

The Economics of Drugs According to the United Nations Office on Drugs and Crime, "[T]he value of the global illicit drug market for the year 2003 was estimated at US$13 bn [billion] at the production level, at $94 bn at the wholesale level (taking seizures into account), and at US$322bn based on retail prices and taking seizures and other losses into account." According to the United Nations Office on Drugs and Crime, "[T]he value of the global illicit drug market for the year 2003 was estimated at US$13 bn [billion] at the production level, at $94 bn at the wholesale level (taking seizures into account), and at US$322bn based on retail prices and taking seizures and other losses into account." This is larger than the total economies of 88% of the countries in the world! This is larger than the total economies of 88% of the countries in the world! Source: United Nations Office on Drugs and Crime (UNODC), World Drug Report 2005 (Vienna, Austria: UNODC, June 2005), p Source: United Nations Office on Drugs and Crime (UNODC), World Drug Report 2005 (Vienna, Austria: UNODC, June 2005), p. 127.

Average % THC in Marijuana Seizures Recent seizures in Atlanta had plants with 18% THC content.

The Forensic All Stars  Mathieu Orfila ( )  Father of toxicology  Alphonse Bertillon ( )  First system of personal identification  Francis Galton ( )  Classification of fingerprints  Dr. Karl Landsteiner( )  Determination of blood groups  Nobel Prize

Alphonse Bertillon’s work in human stature

The Forensic All Stars  Calvin Goddard ( )  Father of ballistics  Use of comparison microscope  Albert S. Osborn ( )  Fundamental principles of document examination  Walter C. McCrone ( )  Application of microscopy to analytic problems

The Forensic All Stars  Hans Gross ( )  First text detailing application of science to criminal investigation  Edmond Locard ( )  Locard’s Exchange Principle  There is an exchange of materials whenever two objects come in contact

Who are the all-stars now? Dr. Henry Lee Dr. Henry Lee Dr. Michael Baden Dr. Michael Baden Dr. Bill Bass Dr. Bill Bass Others? Others?

The River Dell Doctor Dr. Jascelevich Charged with 1 st degree murder of patients. Charged with 1 st degree murder of patients. Trial led to mistrial as evidence was lacking. Trial led to mistrial as evidence was lacking. Curare muscle relaxer. Used on patients but also used for research on animals by Dr. J Curare muscle relaxer. Used on patients but also used for research on animals by Dr. J

Scientific tests for the presence of by product of curare insuffiencient. Scientific tests for the presence of by product of curare insuffiencient. Mistrial- charges dismissed Mistrial- charges dismissed Second trial 10 yrs. Later b/c tests for by product of curare now sufficient. Second trial 10 yrs. Later b/c tests for by product of curare now sufficient. Exhumed bodies- only some chemical found. Exhumed bodies- only some chemical found. Acquitted Acquitted

What is Science? An organized body of knowledge about nature An organized body of knowledge about nature A method for exploring nature and the order in it A method for exploring nature and the order in it A set of tools for solving problems about nature A set of tools for solving problems about nature