Forensic Trace Evidence Review

Paint Evidence

100

Common types of crime scenes where paint evidence is found.

Hit & run, breaking and entering, and identifying forgeries 

200

Color, thickness, and the texture of the paint can be analyzed which laboratory tool?

a. infrared spectroscopy

b. pyrolysis gas chromatography

c. solvent tests

d. a light microscope

d. a light microscope

300

Freebie

Freebie

400

How is the pyrolysis gas chromatography device different than the GCMS?

a. it has a GC column

b. it has an ion source

c. it has a pyrolyzer

d. it has a detector

c. it has a pyrolyzer

500

Gas chromatography is a technique used to separate and identify chemical compounds. There are different methods to analyze different types of compounds. Which of these techniques would be used to analyze paint evidence from a hit and run?

1. Gas chromatography                          
2. Pyrolysis gas chromatography
3. Thin layer chromatography
4. High performance chromatography

                      

b. Pyrolysis gas chromatography

Hair Evidence

100

The two parts of the hair?

Follicle & Shaft

200

The hair of the attacker was observed under the microscope. What can be concluded about the hair?

a.The hair was shed naturally during the attack

b.The hair is from a long-haired male

c. The hair is from an individual that dyes their hair

d. The hair was forcible removed

d. The hair was forcible removed

300

Police responded to an attempted rape. The suspect ran away after the victim managed to fight him off. The investigators were able to collect samples of the perpetrator’s hair from the victim. Which of these characteristics of the attacker can be hypothesized from the hair sample collected?

1. Age                                        
2. Gender
3. Height                        
4. Race

D

400

1. Hair samples from humans and other mammals can look similar with the naked eye. When observed under a microscope the differences in the medulla can be observed. Which of these hair samples is most likely human?

D

500

The cuticle pattern of different mammal hairs can help narrow down the species when identified with a microscope. Which of these represents the cuticle?

B

Fiber Evidence

100

The most common fiber.

Cotton.

200

Name four common places fibers can be found at a crime scene

 Chairs, Rugs, Bedding, & Carpets?

300

Since the chemical analysis of the dye in a fiber makes it possible to trace the fiber back to a specific manufacturer, fibers have these evidential characteristics.

a. Individual

b. Class

c. Group

d. Physical

1.  Individual

400

Fibers are placed into two categories, natural and synthetic. Determining this characteristic can help a forensic scientist narrow down the type of fiber. Which of the following is a natural fiber?

1. Acetate                                               
2. Silk
3. Nylon
4. Rayon            

                                              

Silk    

500

Dr. Spock is examining fiber evidence found at a crime scene. He decides to use the burn method to determine what kind of fibers he has. The fiber curls when approaching the flame, burns relatively slowly, smells like hair, and leaves a hard-little bead afterward. What kind of fiber has Dr. Spock found?

1. Wool                                      
2. Cotton
3. Rayon
4.  Polyester

1. Wool                                      

Glass Evidence

100

Most glass today is called 

• tempered glass
• stained glass
• crystalline glass 
• float glass

float glass

200

It is often important to determine the sequence of shots when analyzing glass fractures. Identify which shot was fired first. Support your claim with appropriate evidence and scientific reasoning.

A was the first shot because the radial fractures of A stop the radial fractures of B.  Since the radial fractures from B cannot pass the radial fractures of A this means A would have been there first.

300

One method of comparing glass samples is the flotation method. Which of these properties of glass can be determined using this method?

1. Birefringence                                     
2. Density of glass
3. Refractive Index                                            
4. Chemical properties

B

400

Glass items often get broken during a struggle at the scene of a crime. Technicians will use a process known as fracture matching to put the item together. This works a lot like putting together a puzzle. What can the technicians learn from fracture matching?

By putting together the pieces of the object, technicians may be able to determine what the object was.

500

Glass shards are placed in different liquids of known refractive indices to calculate the glass’s refractive index. Scientists look for the absent or presence of a dark outline as shown to the right. Identify the name of this line.

a. Fault line                              

b. Density

c. Becke line                          

d. Aqueous line

c. Becke line                          

Miscellaneous

100

Can lip prints be considered to have individual characteristics? Y/N

Yes

200

A mineral is defined as any naturally occurring crystalline solid. T/F

True

300

The first step in examining the soil

Identifying the color.

400

What are the 3 textures of soil?

Sand, Clay, & Silt

500

Identify which suspect best matches the crime scene evidence.

 Suspect 2 best matches the crime scene because each of the 3 bands share the same density as the crime scene sample.