Forensic Science: Crime Lab Techniques, Evidence Analysis, and Key Scientists

Forensic Science

The application of science in the criminal and civil laws that are enforced by police in the criminal justice system.

August Vollner

Police Chief in Berkeley who started an institute for criminology and criminalistics in 1923.

FBI National Laboratory

Opened in 1932, it is the world's largest laboratory for forensics, operating under J Edgar Hoover.

Basic Services of Crime Laboratory

Includes Physical science, Biological Science, Ballistics, Document Examination, Toxicology, Polygraph, Latent fingerprints, and Voiceprint Analysis.

Physical Science

Uses chemistry, physics, and geology to identify and compare crime-scene evidence.

Biological Science

Identifies and performs DNA profiling, dried bloodstains, body fluids, hair, and fiber identification.

Ballistics

Examines firearms, discharged bullets, cartridge cases, shells, and ammunition.

Document Examination

Studies handwriting and typewriting to ascertain authenticity or source.

CSI

Collects and preserves physical evidence.

Toxicology

Examines body fluids and organs to determine the presence of drugs and poisons.

Polygraph

An interrogation tool that is not admissible in court.

Latent fingerprints

Examines evidence for fingerprints.

Voiceprint Analysis

Breaks the human voice into sound patterns unique to an individual.

Forensic Pathology

Involves the investigation of sudden, unnatural, unexplained, or violent deaths.

Cause of death

A determination made by forensic scientists, including medical examiners and coroners.

Autopsy

The medical dissection and examination of the body to determine the cause of death.

Categories of Death

Includes natural, homicide, suicide, accident, or undetermined.

Rigor Mortis

The stiffening of muscle mass that begins within 24 hours of death and disappears within 36 hours.

Liver Mortis

The settling of blood in areas of the body closest to the ground, indicating if a corpse has been moved.

Algor Mortis

The cooling of the body temperature until it reaches ambient or room temperature at a rate of 1-1.5°F/hour.

Potassium levels in the ocular fluid

Cells within the inner surface of the eyeball release potassium into the ocular fluid at a measurable rate.

Forensic Anthropology

Reveals gender, approximate age, race (ancestry), and skeletal injury.

Facial Reconstructions

Can produce facial reconstructions.

Forensic Entomology

The study of insects and the relation to a criminal investigation.

Insect Identification

They can identify specific insects and approximate how long a body has been left exposed.

Forensic Psychology

Examines the relationship between human behavior and legal proceedings.

Competency in Civil Cases

In civil cases, they determine whether or not an individual is competent to make decisions (ex: preparing a will).

Competency in Criminal Cases

In criminal cases, they evaluate behavior disorders and determine if the defendant is competent to stand trial.

Odontology

Practitioners help identify victims based on dental evidence when the body is unrecognizable and bite mark analysis.

Forensic Engineering

Concerned with failure analysis, accident reconstruction, and origins of fires and explosions.

Crime Scene Recreation

Recreating crime scenes and event order.

Computer/Digital Analysis

Identifying, collecting, preserving, and examining information derived from electronic devices.

Functions of a Forensic Scientist

Half of the job is analyzing physical evidence, and the other half is persuading the jury to accept the conclusions.

Analyzing Physical Evidence

When analyzing, always will be bias and error based on scientific method.

Admissibility of Evidence

The procedure, technique, or principles must be 'generally accepted' by scientific community - good science - Frye standard.

Rule 702

Who can give expert testimony - based on experience.

Judging Scientific Evidence

Can it be used in court based on several criteria.

Testing of Scientific Technique

Has the scientific technique/theory been tested.

Peer Review

Subject to peer review.

Rate of Error

Technique's potential rate of error (never 100% confidence).

Existence of Standards

Existence and maintenance of standards.

Acceptance in Scientific Community

Theory/method is accepted in scientific community.

Madrid Bombings

On March 11, 2004, ten bombs exploded on commuter trains in Madrid, killing nearly 200 people and injuring thousands.

Fingerprint Visualization Technique

Investigators used super glue fuming (cyanoacrylate) to develop the print; its limitation is that the process can produce smudgy or unclear ridges.

FBI Fingerprint Match

They matched the fingerprint to Brandon Mayfield, a lawyer from Oregon.

True Responsibility for Madrid Attack

Spanish police later identified the print as belonging to an Algerian man involved in the bombing, not Mayfield.

New Fingerprint Technology

New optical methods that can capture far more ridge detail without damaging the print; major advantage is reducing the chance of false matches.

Auburn Murder Case

In May 1991, a woman was murdered and her house set on fire; her body showed signs of stabbing, strangulation, and bite marks.

Bite Mark Evidence

Used in forensic investigations to help identify suspects based on bite marks.

Bite mark analysis

Investigators compare bite marks on a victim's body with molds of a suspect's teeth to see if they "match."

Roy Brown

Investigators focused on him early in the case because he had argued with the victim's workplace and bite-mark analysis suggested his teeth could match the wounds.

DNA tests

Later DNA tests on saliva stains from the victim's shirt supported Brown's claim and excluded him.

Exoneration

DNA cleared Brown after he spent years in prison, and he was exonerated.

Virtual autopsy

It's a non-invasive autopsy using CT and MRI scans to look inside the body digitally instead of cutting it open.

CT scanner

CT is good for showing bones and gas pockets.

MRI

MRI shows soft tissue in much greater detail.

Trapped gases

They can reveal injuries and causes of death that would otherwise be hard to see.

Blood cottage

It's a building where scientists recreate crime scenes with real blood to study how spatter forms.

Direction of blood spatter

It can be determined by the shape of the drops — the tail points in the direction the blood was traveling.

O.J. Simpson case

The case of O.J. Simpson, accused of killing his ex-wife Nicole Brown and her friend Ron Goldman.

Compromised evidence

Police and lab workers mishandled the samples — mixing, contaminating, and failing to keep chain of custody.

IC-CRIME

It's a system that digitally reconstructs a crime scene in 3-D so investigators and juries can explore it virtually.

Landlord connection

The reconstruction showed that his version of events didn't match the physical evidence, linking him to the crime.

Carl Wilhelm Scheele

Discovered how to detect arsenic in human tissue, an early toxicology breakthrough.

William Bass

Founded the 'Body Farm' (University of Tennessee Anthropological Research Facility) for studying human decomposition.

William Nichol

Invented the Nicol prism, advancing the use of polarized light microscopy for examining substances, including forensic materials.

Mathieu Orfila

Known as the 'Father of Forensic Toxicology'; systematized testing poisons in human organs.

Karl Landsteiner

Discovered the ABO blood group system, making blood typing possible in forensics.

Cyril Wecht

Forensic pathologist famous for high-profile autopsies; contributed to modern practices in forensic pathology.

Calvin Goddard

Developed comparative ballistics using the comparison microscope to match bullets and firearms.

Albert Osborn

Founder of forensic document examination; established methods for analyzing handwriting and questioned documents.

Alec Jeffreys

Discovered DNA fingerprinting/profiling, revolutionizing forensic identification.

Hans Gross

Wrote the first comprehensive handbook on criminal investigation, integrating science into police work.

Edmond Locard

Formulated the Locard Exchange Principle ('every contact leaves a trace'), foundational to crime scene investigation.