Cjs 215 - Physical Evidence

Physical Evidence

Lea MacDonald

CJS/215

07-30-2012

Anne Leslie

Physical Evidence

Imagine you just arrived at a crime scene. Right away you are able see evidence that may help you determine what happened and get clues as to who did it. Certain steps are going to need to be followed first. When entering you must make sure that no evidence is destroyed or bothered because it could affect the testing, and you need to make sure the process for obtaining that evidence is done without mistakes. Physical evidence could be absolutely anything, so understanding how to collect and preserve evidence and make sure all laws are followed is key in making any evidence liable in court.

Evidence at the Crime Scene

Shell Casings

Shell casings are shells that are ejected by a firearm the same time a bullet is fired. When leaving the gun, it still is marked with impressions when being ejected. When collecting shell casings or any evidence the first thing that needs to be done is making sure you are wearing the correct protection gear. Not only to protect yourself but the evidence as well. After making sure all protective gear is on pictures of the crime scene need to be taken. Pictures, notes, and diagrams of where bullet casings are found can help determine where and how the bullets were fired. When picking up bullet casing extreme caution needs to be used so that no markings are tampered with. After carefully retrieving bullet casings they must be wrapped in tissue before being put into an envelope or container. The envelope must then be properly sealed and labeled before being sent to the lab (Saferstein, 2013, p. 213).

Footprints

In this crime scene, the suspect left three sets of footprints. Two muddy footprints as well as one bloody set of footprints spreading throughout the house. Since we already handled the bullet casing the first step is to make sure our protective gear is replaced. This ensures no cross contamination. Then again pictures need to be taken. If there is debris on the prints photos are needed to be taken before and after the removal of the debris. When taking photos, a ruler needs to be placed to show size in case any evidence is hurt while shipping or making molds. Also, photographs are to be taken from all angles to showcase different textures and markings that may help identify the source of the shoe. When working on a bloody set of prints several steps are taken to remove them if possible. If the print is on carpet you could cut around the show print, so you have the exact print. If you are unable to obtain the actual print, then it must be either lifted or casted. Lifting the footprints is like lifting fingerprints but there are other ways such as electrostatic lifting. With electrostatic lifting you use a piece of mylar paper big enough to cover the area, use a roller to avoid air bubbles and the use the electrostatic unit to lift the print. Because the print contains mud/soil collecting dirt and mud from around the crime scene could help determine locations of where the suspect or victims could have been (Saferstein, 2013, p. 218).

Tire Marks

Since there was a set of tire marks at the scene this must be kept as evidence. It is obvious that taking a piece of asphalt is not possible, so photography and a casting must be made. When taking photographs, it is like that of photographing shoe prints. You want to take the picture using multiple angles and lighting to be able and capture markings. When casting tire prints you want to make sure the tracks are hardened so using hairspray they