Forensic Science .

List two reasons why striations on bullets fired from the same gun may vary slightly.

Besides the barrel, what parts of a firearm may leave distinctive markings on a shell cartridge?

Why does a firearms examiner test-fire bullets from a suspect barrel?

What is distance determination? Describe two situations in which distance determination can establish the facts of a shooting incident.

What evidence does an investigator study to make a distance determination? How can test-firing a suspect weapon help the investigator make a distance determination?

List three characteristics of a bullet hole that indicate that the shot was fired at extremely close range.

What is the Greiss test and what two pieces of information can it provide to an investigator?

How is shot pattern used to make a distance determination for shotgun blasts? What factors other than distance to target can affect the distance determination?

What evidence do investigators look for when trying to determine whether a suspect has fired a handgun? Where is such evidence typically found and why?

Why does analysis of primer residue from a suspect’s hands produce a low rate of positive results? Why is such analysis typically ineffective in locating primer residue from a .22-caliber gun?

Describe how a criminalist restores an obliterated serial number on a weapon.

Why would an investigator not pick up a weapon by its barrel with a pencil or stick in order to protect latent fingerprints? How should suspect firearms be handled in such a situation?

What characteristics of a suspect firearm should an investigator record before unloading it? Why should the investigator number the chambers and cartridges when unloading a suspect weapon?

What is the investigator’s primary concern when collecting and handling bullets and cartridge cases? Why must the investigator exercise extreme caution when removing a bullet lodged in a wall or other object?

Name two types of marks that impart individuality to a tool and explain how the marks are made.

What techniques does an investigator use to analyze tool marks that cannot be removed from a crime scene? What is the disadvantage of this technique?

What is the first thing the investigator does before handling or moving any impression at a crime scene? Why is this considered merely a backup or precautionary procedure?

What kinds of impression evidence might a forensic odontologist be asked to analyze? How might this help identify a suspect?