Chapter 5: The Crime Scene, Forensic Evidence, & DNA quiz review

Physical Evidence

Can be seen and held. It is created as a direct result of the crime

• identifies the victim and perpetrator

• EX: weapon, phone, clothes, fingerprints, DNA

Class characteristic evidence

Shares characteristics with a particular GROUP or class

• EX: Jeep Wranglers as a whole without bumper stickers or registration

• Type of physical evidence

Individual Characteristic evidence

characteristics that can be identified as originating from an individual particular source

• EX: Birthmarks, fingerprints, scars

Primary Crime Scene

The area where the crime ACTUALLY occurred

Secondary Crime Scene

An area where there is SIGNIFICANT EVIDENCE relating to the crime, but not where the crime occurred

• EX: A dump truck, or the house of the subject

Once arriving at the scene, what is the initial response/prioritization?

1. SAFETY/ OFFICER SAFETY

2. Conduct a neighborhood canvas (scanning the neighborhood)

The Investigator in Crime SHOULD

1. require that all personnel follow proper procedures to ensure the safety and integrity of all recovered evidence

2. be responsible for OR supervising the taking of photos, videos, sketches, measurements, and notes

3. determine the order in which the evidence was collected

Biological evidence

Main: Blood, Semen, Saliva, Hair

Other: Fingernail scrapings, skin cells, and touch DNA

Blood

Can be found virtually ANYWHERE in crime scenes

• most commonly found at serious crime scenes like homicide and assault

Semen

• A seminal fluid that contains sperm.

• Is often found as a result of a sexual crime

Saliva

Consists mostly of water, but also contains mucus, proteins, enzymes, and skin cells.

DNA

generic building block of all living organisms

Mitochondrial DNA (MtDNA)

• Inherited from an individuals mother only

Nuclear DNA

• Form of DNA unique to an individual

• Found in the nucleus of each cell (EX: cheek cells, saliva, blood, semen)

CODIS (Combined DNA Index System)

• national database for FBI containing DNA profiles collected from various sources

Fingerprints

consist of rides, depressions, and separations

Fingerprint patterns

loops, whorls, and arches

Fingerprints in criminal investigations

1. Visible TRANSFERRED prints

2. Visible IMPRESSION Prints

3. LATENT PRINTS (oil, dirt) (Only seen on smooth surfaces)

Collection methods for fingerprints

Fine powder to revel the print and lift it with an adhesive tape

AFIS

• Stores collected fingerprints to help identify perpetrators

• FBI controls this

Criminalistics

The Science of physical evidence

• Trace evidence

Forensic Pathology

The science of DEAD bodies and autopsies

Forensic Anthropology

The Identification of skeletal remains of humans

Forensic Ondotology

The application of dentistry to legal matters

Forensic entomology

the science of insects in answering legal questions, especially time of death