Law - Chapter 7 Investigation and Arrest

Three tasks the police must complete when they arrive at a crime scene

1. Call ambulance to help any injured people at the scene

2. Call reinforcements to help deal with any dangers that pose as a risk

3. Continue search even when the perpetrator has left.

Two boundaries the police establish at a crime scene

The center and perimeter. The center is where the offence was committed. The perimeter is where the accused may have been present or where they have left evidence

Contamination of Evidence

Refers to the alteration or introduction of foreign materials to evidence gathered at a crime scene, which can compromise the integrity and reliability of that evidence.

Example of contaminated evidence

Fingerprints on a knife that was found at the scene of the crime that was used by the accused. This hurts the Crown’s case against the accused because there is evidence that the knife was used by the accused

Use of police log

To document the police’s daily activities that helps them recall events, especially useful when testifying for trials

Patrol officer

Maintains order and protects a community by enforcing laws. Assigned to an area to prevent illegal activity and ensure safety for citizens.

e.g. Direct traffic, write tickets, investigate accidents and crimes and respond to calls for help.

Criminal identification officer

Collects, analyzes, classifies, and photographs physical evidence and fingerprints to identify the criminal. They are at the scene of crime and obtains evidence.

Physical evidence

Carries more weight in a court of law because you can see the evidence, which proves/disproves facts about the offence

Witness testimony

Evidence spoken by a witness, carries less weight in court because it can be inaccurate

Class characteristics

Not unique to a single object, places particular bits of evidence into a group of objects

Individual characteristics

Narrow down the evidence to a single individual source

Process of “lifted” latent fingerprints

Latent fingerprints are formed by the skin’s natural oils and perspiration.

1. Dust the surface of where the fingerprints could be found using a fingerprint powder

2. Remove any excess powder by blowing on the surface with a small can of compressed air or by brushing lightly across the surface.

3. Use adhesive tape and stick it to the suspected area to “lift” the fingerprints

4. Put the adhesive tape onto a white cardboard surface

Most common body substance found at a crime scene

Blood

DNA profiling