The Organization of a Crime Laboratory

Growth There are approximately 320 crime labs in the US; more than 3 times the number than in 1966

Reasons for Growth Increasing growth of physical evidence recovered from crime scenes as a result of rising crime rates. The need to perform chemical analysis on drugs, coupled with a significant increase in illicit drug seizures (all drug seizures must have confirmatory chemical analysis before case can go to court)

Supreme Court decisions have enhanced the rights of the defendant’s right to counsel and right to remain silent, have encouraged police agencies to place a greater reliance on scientific investigative techniques. Advances in scientific technology have provided forensic scientists with many new skills and techniques to extract meaningful information from physical evidence. (DNA profiling)

Organization Sizes vary from staff of 1 to 100 Labs in the US are decentralized, under the direction of federal, state, county, and municipal governments

Federal Crime Laboratories FBI – largest crime lab in the world, broad investigative powers DEA – analysis of drugs seized in violation of federal laws regulating production, sale & transport, of drugs Bureau of Alcohol, Tobacco, Firearms & Explosives – analyzing alcoholic beverages & documents relating to tax law enforcement & for examining weapons, explosive devices & related evidence

U.S. Postal Inspection Service – criminal investigations relating to the postal service.

State Most states maintain a crime lab to service local agencies that don’t have access to one. Some states have statewide comprehensive system of regional or satellite labs under the direction of a central facility

Local Provide service to county & municipal agencies Usually independent of state and financed by local government

Services of the “Full Service” Crime Lab 1.Physical Science Unit: a.Uses principles and techniques of chemistry, physics, and geology to identify & conduct comparisons of crime-scene evidence b.Items examined include: a.Drugsd. explosives b.Glasse. soil c.Paintf. trace evidence

2. Biology Unit: a. Identification & DNA profiling from body fluids b. comparison of hair & fibers c. identification & comparison of botanical materials ( ex. wood and plants)

3. Firearms unit: a. examination of firearms, discharged bullets, cartridge cases, shotgun shells, and ammunition of all types b. examination of garments and other objects to detect firearm discharge residues & to approximate the distance from a target at which a weapon was fired c. examination of marks made by tools

4. Document Examination Unit a. handwriting & typing of questioned documents b. analysis of paper & ink c. Indented writings (partially visible depressions on sheet of paper underneath one where writing is visible), obliterations, erasures & burned/charred docs

5. Photography Unit: a. examine & record physical evidence b. Prepare photographic exhibits for courtroom presentations c. may use special photographic techniques (digital imaging, infrared, UV photography, X-ray photography) to make information invisible to naked eye become visible

Optional services provided by full service lab 1. Toxicology unit – examine body fluids & organs to determine presence of drugs & poisons (may be done at Medical Examiners or Coroner’s office). This department may train operator’s & maintain field instruments like Intoxilyzer (determines alcohol level)

2. Latent Fingerprint Unit – process and examine evidence for latent (invisible) fingerprints 3. Polygraph Unit – “lie detector”- more a tool of criminal investigator than forensic scientist, often found in the forensic lab 4. Voiceprint Analysis Unit – use sound spectograph to turn speech into visual graphic display called voiceprint – displays the uniqueness of individual sound patterns

5. Evidence Collection Unit – evidence collection by forensic science service is gaining recognition. Trained personnel collect & preserve physical evidence for processing at lab.

Functions of the Forensic Scientist A.Analysis of Physical Evidence 1. Apply scientific techniques to analysis of evidence 2. Be aware of demands and constraints of legal system

Constraints of Legal System Frye v United States: set precedent Court must decide if the questioned procedure/technique/principle is “generally accepted” by a meaningful segment of the scientific community (systolic blood pressure deception test)

Constraints of Legal System Daubert v Merrell Dow Pharmaceutical, Inc.: US Supreme Court asserted that in assessing the admissibility of new and unique scientific tests the trial judge did not have to rely solely on the concept of “general acceptance” (of the Frye Standard)

Constraints of Legal System Kumho Tire Co, Ld v Carmichael – the Court rated that the “gatekeeping” role of the trial judge applied not only to scientific evidence, but to all expert testimony

B. Provision of expert testimony 1. Expert witness – an individual whom the court determines possesses knowledge relevant to the trial that is not expected of the average personExpert witness 2. Competency shown by degrees held, professional organizations belong to, professional articles published, years of experience, participation in special courses Functions of the Forensic Scientist

Expert Witness 3. Opposing attorney may cross-examine the witness & point out weaknesses in background or knowledge 4. Laypersons testifying may not state their opinion, but an expert witness can

Functions of the Forensic Scientist C. Furnishing Training in the Proper Recognition, Collection, & Preservation of Physical Evidence 1. often have Evidence Technicians on 24 hour call to aid criminal investigations in retrieving evidence 2. where patrol officers or detectives gather the evidence, forensic scientist should train all officers engaged in fieldwork

Other Forensic Science Services 1.Forensic pathology – investigation of sudden, unnatural, unexplained or violent deaths. Primary role of medical examiner or coroner is to establish cause of death. If can’t establish through observation, may do autopsy

Forensic Pathology Manner of death categories: natural homicide suicide accident undetermined

Forensic Pathology stages of decomposition - to estimate time of death 1. rigor mortis – the medical condition that occurs after death & results in shortening of muscle tissue & stiffening of body parts in the position they are in when death occurs - 24h,

Forensic Pathology 2. livor mortis – human heart stops pumping and blood settles in the body in areas closest to the ground. - skin will appear dark blue or purple in these areas -skin doesn’t appear discolored in areas where body is restricted (clothes, or object pressed against body) - begins immediately & up to 12h after death - helps determine if body has been moved.

Forensic Pathology 3.algor mortis – post mortem changes that cause a body to lose heat – cools until reaches room temp. -rate is influenced by factors: size of body, weather condition, clothes, etc. so not always precise - drops about 1.5 degrees F per hr.

Forensic Pathology 4. potassium levels in ocular fluid (vitreous humor) after death: cells inside eye release K into ocular fluid. -analyze amount of K intervals after death to determine rate of K released into vitreous humor -can estimate time of death 5. amount of food in stomach determines when last meal eaten

Forensic Anthropology identification and examination of human skeletal remains. reveals origin, sex, approximate age, race & skeletal injury may create facial reconstruction

Forensic Entomology study of insects & their relation to criminal investigation - estimate time of death by blow fly life cycles - affected by weather conditions & climate

Forensic Psychiatry relationship between human behavior and legal proceedings is examined. civil cases – determine whether people are competent to make decisions like: - will, settling property, refuse medical treatment

Forensic Psychiatry criminal cases – evaluate behavioral disorders, determine whether competent to stand trial also examine behavioral patterns, develop criminal profile

Forensic Odontology identification of victims by examining teeth, dental records analyze bite marks, compare to suspect’s teeth structure

Forensic Engineering failure analysis, accident reconstruction, causes & origins of fires or explosions, - examine accident scenes, review photographs, inspect mechanical objects Who was responsible? How did an accident or structural failure occur?