Question 1

When a gun is recovered from an underwater location, it should be:

Accepted Answer

Transporting a gun recovered from an underwater location in a container with enough of the same water necessary to keep it submerged helps preserve any forensic evidence that may be present on the gun. Changing the gun's environment abruptly by drying it or exposing it to different water can alter or destroy valuable evidence such as fingerprints, blood, or other biological materials.

Question 2

Shoe and tire marks impressed into soft earth can be best preserved by:

Accepted Answer

A

Question 3

The reason grooves are rifled into the bore of a gun is so that a:

Accepted Answer

Rifling grooves are cut into the bore of a gun to impart a spin to the bullet. This spin stabilizes the bullet in flight, ensuring it follows a true and accurate path towards the target.

Question 4

To prevent the disturbance of latent fingerprints on a firearm, the weapon should be lifted by:

Accepted Answer

The edge of the trigger guard or the checkered portion of the grip are less likely to have latent fingerprints, minimizing the risk of disturbing them.

Question 5

Distinctive markings of shells and cartridges can be made by the:

Accepted Answer

All of the above components can leave distinctive markings on shells and cartridges. The extractor and ejector mechanism, firing pin, and breechface can all impart unique marks that can be used for forensic analysis in firearm identification.

Question 6

Two-dimensional imprints found at a crime scene can be lifted using:

Accepted Answer

An electrostatic lifting device is specifically designed to lift two-dimensional imprints, such as footprints or tire marks, from surfaces at a crime scene.

Question 7

What is NIBIN?

Accepted Answer

NIBIN, the National Integrated Ballistic Information Network, is a database used by law enforcement agencies to capture and compare ballistic evidence to aid in solving crimes involving firearms.

Question 8

Generally speaking, the amount of gunpowder particles found around a bullet hole is ________ to the distance from which the weapon was fired.

Accepted Answer

The amount of gunpowder particles found around a bullet hole is directly related to the distance from which the weapon was fired. Closer shots deposit more gunpowder particles around the entry point.

Question 9

The comparison of two bullets is possible with the comparison microscope. Such a study is made difficult by the fact that:

Accepted Answer

All the options listed (A, B, and C) are factors that can make the comparison of bullets difficult. Lands and grooves wear over time, bullets can be distorted upon impact, and foreign materials like grit and rust can alter bullet markings.

Question 10

When an etching agent is applied to a metal surface in order to restore a removed serial number, the stamped area will dissolve at ________ the unstamped area.

Accepted Answer

When an etching agent is applied to a metal surface, the stamped area (where the metal has been deformed and stressed) will dissolve at a greater rate than the unstamped area, revealing the serial number.

Question 11

Generally, the gauge of a shotgun is ________ to the diameter of its barrel.

Accepted Answer

The gauge of a shotgun is directly related to the diameter of its barrel, with a smaller gauge number indicating a larger barrel diameter.

Question 12

Which technique of detecting gunshot residue holds the most promise for the immediate future?

Accepted Answer

SEM (Scanning Electron Microscopy) primer residue detection is currently the most promising technique for detecting gunshot residue. It allows for the detailed analysis of particles that are characteristic of gunshot residue, providing both elemental composition and morphology, which makes it highly reliable and useful for forensic investigations.

Question 13

The likelihood of detecting gunshot residue on swabs taken from living subjects more than six hours after a firing has occurred is ________ the likelihood of detecting gunshot residue within two hours of a firing.

Accepted Answer

The likelihood of detecting gunshot residue on swabs taken from living subjects decreases over time due to factors such as activity, washing, and environmental exposure. Therefore, it is less likely to detect gunshot residue more than six hours after a firing compared to within two hours.

Question 14

Which is NOT a class characteristic of a suspect's sneaker?

Accepted Answer

Class characteristics are features that are not unique to a particular object but can place it into a category, such as brand, color, and size. Wear marks, however, are individual characteristics that can be unique to a specific item, reflecting its use and history.

Question 15

Tools and tool marks are often found at burglary scenes and can be useful evidence. Proper evidence collection by the field investigator would include:

Accepted Answer

Photographing and casting tool marks preserve the evidence for further analysis without altering or contaminating it.

Question 16

The "dermal nitrate test" has fallen into disfavor because of its lack of specificity. Which of the following common materials does NOT give a misleading positive reaction to this test?

Accepted Answer

The answer of The "dermal nitrate test" has fallen into...

Question 17

The barrel of a shotgun:

Accepted Answer

Shotgun barrels are smooth on the inside, lacking the rifling (grooves and lands) that rifles have, which gives them their name and distinguishes their barrels. Rifling spins bullets for stability and accuracy, while shotguns fire shot or slugs without this need.

Question 18

Discharged evidence bullets must be carefully handled to avoid damage to the:

Accepted Answer

Striation markings are the fine lines or grooves found on the surface of a bullet after it has been fired from a gun. These markings are unique to the gun's barrel and are crucial for forensic ballistics analysis to match a bullet to a specific firearm. Handling bullets carelessly can alter these markings, making it difficult or impossible to link the bullet to the weapon it was fired from.

Question 19

Gunpowder residue patterns can be detected by:

Accepted Answer

Gunpowder residue patterns can be detected by both the Griess Test, which is a chemical test that can detect nitrites (a common component of gunpowder residue), and IR (infrared) photography, which can capture the unique spectral signature of gunpowder residues that might not be visible to the naked eye.

Question 20

Chokes are sometimes found on shotguns where they function to constrict the end of the barrel. The speed and distance traveled by pellets fired from a narrow choke is ________ the speed and distance traveled by pellets fired from a shotgun with a wide choke.

Accepted Answer

Chokes constrict the end of the barrel, focusing the shot tighter together as it leaves the barrel. This can increase the effective range and speed of the pellets because the shot stays together longer, reducing spread and maintaining velocity over a greater distance.

Quiz 9: Firearms, Tool Marks, and Other Impressions