ETC ETC Biological & DNA Evidence 2

Question 1

What is the purpose of the Combined DNA Index System (CODIS)?

Accepted Answer

A national database that stores DNA profiles to link crime scene evidence to known offenders or unsolved cases

Answer

CODIS is the FBI-managed national DNA database that contains profiles from convicted offenders, arrestees, and forensic unknowns, enabling matches between crime scenes and known individuals.

Question 2

When collecting a buccal swab (DNA reference sample) from a suspect, which area of the mouth is swabbed?

Accepted Answer

The inner cheek (buccal mucosa) using a firm rotational swabbing motion

Answer

Buccal swabs collect epithelial cells from the inner cheek (buccal mucosa), providing a clean reference DNA sample; multiple swabs from both cheeks may be collected.

Question 3

Bloodstain pattern analysis (BPA) can help investigators determine which of the following?

Accepted Answer

The direction, speed, and origin of blood shed at the crime scene

Answer

BPA examines the size, shape, distribution, and directionality of bloodstains to reconstruct the events that produced them, including point of origin and movement.

Question 4

What type of bloodstain results from blood dripping into existing blood at a lower velocity?

Accepted Answer

Satellite spatter pattern with secondary droplets around the primary stain

Answer

When blood drips into pooled blood, secondary satellite droplets are produced around the primary stain, indicating blood dripping at low velocity onto a wet surface.

Question 5

Which biological sample from a suspect provides the longest window for detecting alcohol consumption?

Accepted Answer

Hair (EtG in hair — up to 90 days)

Answer

Ethyl glucuronide (EtG) incorporated into hair can detect alcohol consumption for up to 90 days, far exceeding blood, urine, or saliva windows.

(ETC) Evidence Technician Certification Practice Test

(ETC) Evidence Technician Certification Practice Test

ETC ETC Biological & DNA Evidence 2