Forensic Science Exam 1

CSI shows

Portray 90% fiction; not good reflections of actual crime investigations.

American Academy of Forensic Sciences

Largest forensic science organization in the world that promotes integrity, education, and research.

Mathieu Orfila

Father of forensic toxicology; authored a treatise on detection of poisons in 1814.

Alphonse Bertillon

Devised the first scientific system of personal identification using anthropometry.

Leone Lattes

Developed a procedure to determine blood type for dried bloodstains.

Edmond Locard

Formulated the Locard exchange principle: when two objects contact, material exchanges occur.

• This concept is the locard exchange principle-basis for transfer of evidence

Frye v. US

Set guidelines that evidence must be processed using techniques generally accepted by the scientific community.

Daubert v. Merrell Dow Pharmaceuticals

Supreme Court ruling that evidence must meet additional standards beyond Frye for admissibility.

Impact spatter

Blood pattern that occurs when an object impacts a source of blood.

Area of convergence

Point in a two-dimensional plane from which blood drops originated.

Individual characteristics

Unique features in evidence that can identify it to the exclusion of all others, e.g., fingerprints.

Physical evidence

Any object that can establish a link between the victim and the perpetrator.

Crack vs. Cocaine

Cocaine is a salt; crack is cheaper and more popular among low-income households.

Expert testimony

Forensic scientist's required explanation of methods, results, and conclusions in court.

Arterial spray spatter

Blood pattern caused by injury to the heart or main artery, brighter in color.

Flow patterns

Made by drops of blood flowing due to the pull of gravity.

Angle of impact equation

Sin A = width of bloodstain / length of bloodstain.

Impact pattern classification

Classified by droplet size and velocity: low, medium, and high velocity.

Expirated bloodstain pattern

Forcefully expelled blood from the victim due to trauma.

4 major Federal Crime Labs

• FBI

• DEA (drug enforcement administration)

• ATF (bureau of alcohol, tobacco, firearms and explosives

• US postal inspection service

Standard

• Physical science biology

• Firearms

• Documents

• Photography

Optional

• Toxicology

• Fingerprints

• Digital evidence

advantages of digital imaging

• Instant access

• Integration

• No film processing

disadvantage of digital imaging

dismissability

forward spatter

projected outward and away from the source

back spatter

also known as blow-back spatter, projected backwards from the source

What happens if a bullet does not exit the body?

a gunshot produces only back spatter

Arterial spray spatter

caused by am injury to the heart, or main artery and is generally brighter in color

expirated blooodstain pattern

forcefully exprelled blood from the nose or mouth that has accumulated in the lungs, sinuses, and airway passages of the victim as a result of trauma

area of convergence

the point on a two-dimensional plane from which the drops in an impact pattern originated

area of origin

an impact bloodstain pattern is the area in a three dimensional space from which the blood was projected

identification

Determine the physical or chemical identity with as near absolute certainty as existing analytical techniques will permit.

associated criminal behavior with location

passive vs. active (more crime in certain areas)

The five different types of units in the crime labs

• biology

• physical science

• serology

• trace evidence

• firearms

The “general acceptance” principle, which serves as a criterion of the judicial admissibility of scientific evidence, was set forth in the case of __________________.

Frye v. United States

Three methods for recording the crime scene are

Photography, sketching, notes

The crime scene notes should include a precise record of personnel movements in and out of the scene starting with the ______.

first responding officer

Before located evidence is collected, it must be fully described in the investigator's _____.

Notes

Photographs of physical evidence must include overviews as well as __________ to record the details of objects.

Close-ups

The most commonly used camera for crime scene photography is the __________ camera, which can be film or digital.

Single Lens Reflex

A digital camera captures light on each of millions of tiny picture elements called __________.

Pixels

The succession of photographs taken at a crime scene is __________ photographs first and __________ photographs last.

Overview; close-up

To ensure that their digital images will be admissible, many jurisdictions have developed or are developing __________ for the use of digital photography to avoid the possibility of enhancement or doctoring of crime scene photographs.

Standard Operating Procedures

A detailed search of the crime scene for physical evidence must be conducted in a(n) __________ manner.

Systematic

Besides the more obvious items of physical evidence, possible __________ of trace evidence must be collected for detailed examination in the laboratory.

Carriers

In Kumho Tire Co., Ltd. v. Carmichael, the U.S. Supreme Court ruled that the "gatekeeping" role of a trial judge:

Applied to all expert testimony