the policy and procedure for collecting fingerprint evidence and firearms and ammunition

Solution Preview

Please explain the policy and procedure for collecting fingerprint evidence and firearms and ammunition. Please provide references.

Dactyloscopy is the technique of comparing fingerprints, typically those found at the setting of a crime and those of a suspect. Due to the uniqueness of the fingers' and hands' papillar lines, it is generally considered a reliable method of identifying a person. Croat-Argentine Juan Vucetich perfected dactyloscopy in late 19th and early 20th century. When a person touches something with his fingers, there will usually be a visible or invisible residue left on the touched surface. The residue is patterned as a copy of the person's fingerprint and can be collected for visual study and comparison. Traditionally, finely ground powders of chalk or coal have been used to make the fingerprint clearly visible. The powder adheres to the fingerprint residue but not the surrounding surface. Sometimes the prints are invisible, in which case they are called "latent fingerprints". There are chemical techniques such as cyanoacrylate fuming and ninhydrin spray that can help make them visible. There are three basic fingerprint patterns: Arch, Loop and Whorl. There are more complex classification systems that further break down the pattern to plain arches or tented arches. Loops may be radial or ulnar. Whorls also have smaller classifications. However, the five most commonly used are: whorl, radial loop, ulnar loop, arch and tented arch. A fingerprint is an imprint made by the pattern of ridges on the pad of a human finger. These ridges are known as dermal ridges. Dermal ridges are not unique to humans, however, and some species of primate are also capable of generating fingerprints. Dermal ridges are commonly believed to provide traction for grasping objects. Fingerprints are usually considered to be unique, with no two fingers having the exact same friction ridge characteristics. A person's fingerprint can be used as a biometric method to identify human individuals.
In case of fire arms and ammunition it is important that the investigating officer on the scene identify the following:
Guns:
1. Semi-automatic
2. Revolver
3. Rifle
4. Shotgun
Bullets:
1. Full metal jacket
2. Soft point
3. Hollow point
4. Lead alloy
Cartridge markings:
1. Firing pin
2. Breech block
3. ...