Crime Scene Investigation: Evidence Collection, Documentation, and Chain of Custody

What does maintaining chain of custody mean?

It is a log of the people who have had access to a specific piece of evidence, ensuring it is not improperly tampered with.

What information is included in the chain of custody?

It documents each person and organization who handles an asset, the date/time it was collected or transferred, and the purpose of the transfer.

Who is involved in the chain of custody?

Law enforcement officers, crime scene investigators, detectives, and medical personnel.

What pieces of information are needed for a crime scene sketch to be legally admissible?

Scale, evidence labels, address/location of the scene, case number, date of the sketch, and the name of the person who made it.

Why are sketches important in crime scene investigations?

They provide a bird's eye view of the scene and document distances and dimensions that photos and videos do not capture.

What is the importance of careful evidence collection and preservation?

To prevent contamination or destruction of the evidence.

Why are notes, photographs, and sketches still important despite the use of video in crime scene investigations?

They provide specific details that a video may not capture and allow the jury to see evidence more clearly.

Why might someone stage a crime scene?

To cover up their tracks, such as in cases of insurance fraud.

How can you tell if a crime scene has been staged?

By observing the ground for evidence like stains or marks and using a flashlight at an oblique angle to locate evidence.

Why is it necessary to separate witnesses at a crime scene?

To avoid collusion and skewed perceptions about what they saw.

What is a security log in the context of a crime scene?

A record kept by the crime scene recorder or responding officer of who enters or leaves the crime scene.

Who do lab technicians send their findings to?

The lead investigator.

What type of containers should biological evidence be stored in?

Breathable paper containers, while arson evidence should be stored in airtight metal containers.

What is a double-blind lineup?

A method of presenting suspects to a victim where neither the victim nor the police know who the suspect is to prevent misidentification.

What type of evidence has the Innocence Project used to free wrongly convicted individuals?

DNA evidence.

What are the basic methods used to record a crime scene?

Taking photos, sketching the scene, taking notes, and recording video.

What is the value of photographing a crime scene?

It allows multiple people to observe evidence simultaneously and provides a true and accurate record of the scene.

What is a photomacrographic scale?

A measuring tool used in crime scene photos to show the size of evidence.

What are the proper techniques for collecting and packaging physical evidence?

Most evidence is packaged in a paper bag, sealed, and marked with the investigator's initials, date, case name, and number.

What information should be placed on a container for evidence?

CSI or investigator's initials, date, case name, and number.

What are some collection techniques for trace evidence?

Picking, lifting, scraping, vacuum sweeping, combing, and clipping.

What type of containers are used for most items of evidence?

Paper containers such as packets, envelopes, and bags.

How should guns be stored when collected as evidence?

Secured in a box, ensuring they are not loaded.

What type of containers are used for liquid items?

Non-breakable, leakproof containers.

How should arson evidence be collected?

In air-tight, clean metal cans.

What is the protocol for collecting moist or wet evidence?

It can be collected in plastic containers if transported within two hours, then must be air-dried and repackaged in dry paper containers.

What are the 7 S's of crime scene investigation in order?

Secure, separate, scan, see, sketch, search, and secure and collect evidence.

What are two examples of direct evidence?

Video tape evidence of a crime and an eyewitness statement.

What are two examples of circumstantial evidence?

Blood type and shoe prints.

What is the purpose of wearing protective gear during crime scene investigation?

To avoid destruction or contamination of evidence.

What are the three ways to photograph a crime scene?

Evidence in relation to the overall scene, evidence in relation to the victim, and close-ups with a ruler from different angles.

What is the correct packaging for a cell phone?

Plastic bag.

What is the correct packaging for blood spatter evidence?

Paper envelope.

What is the correct packaging for materials taken from a fire?

Airtight container, usually metal.

What is the error in Case 1 regarding the crime scene sketch?

The sketch artist forgot to include windows and did not measure the size of evidence.

What was done incorrectly in Case 2 with the damp, bloody shirt?

The shirt was not allowed to dry before being stored in a sealed evidence bag.

What mistake was made in Case 3 regarding the hair evidence?

The collector did not sign his name across the tape before completing the log.

Why is it important to take standard reference samples from various individuals?

To exclude all others from the suspect list.