tire track evidence, this is where from the tire tracks that were seen by the entrance of the house and the three set of foot prints which were muddy. There was also trace evidence that was obtained from the mud that was in the set of foot prints. There was also firearm evidence that can be based on the shell casings that were collected at the crime scene. The importance of the preservation and collection of firearm evidence will be discussed and what it can uncover. There are certain legal issues that play into effect when accessing a potential crime scene and collecting potential evidence. Finally, the significance of physical evidence and how it plays a part in solving crime. Witnesses may forget facts or have different versions of what happened, but physical evidence, when properly documented, photographed, collected, and preserved, remains unchanged and can be used years after the crime has occurred. The physical evidence that was found at this crime scene was shell casing, tire tracks and two muddy sets of footprints. Biological evidence, which falls under physical evidence as well, was found at the crime scene. This evidence was bloody finger prints and a set of bloody footprints. Once the crime scene has been documented, photographed, locations of evidence noted, the collection process can proceed. The crime scene should be photographed in high resolution. The bloody fingerprints and set of bloody footprints should be collected first, since blood will dry. There are two different types of blood that can be collected at a crime scene: liquid and dried blood. Liquid blood evidence is generally collected from blood pools but can be collected off of clothing as well, using a gauze pad or a sterile cotton cloth. Once the sample is collected it must be refrigerated or frozen and brought to the laboratory as quickly as possible. The sample must first be dried thoroughly at room temperature. It is important to get the sample to the laboratory as quickly as possible because after 48 hours the sample might be useless. If the sample has to be mailed it should be completely air dried before packaging. Dried bloodstains can be found on small objects, larger objects and on clothing. When dried blood is found on a small object the entire object can be sent to the lab after it’s been properly packaged and labeled. When dried blood is found on a larger object that is transportable, an investigator should cover the stained area with paper and tape the paper to the object to avoid contamination. Shoeprints and tire tracks can be matched positively to a pair of shoes or to tires in a suspect's possession. Shoeprints and tire tracks can sometimes tell investigators what type of shoes or tires to look for when searching a suspect's residence or vehicles. Before any attempt is made at collecting shoeprints or tire tracks, one-to-one photographs should be made using a tripod, ruler, and level. The flash should be held at about 45 degree angles from the surface containing an impression. Casts can be made of impressions using dental stone. Once hardened, the cast can be packaged in paper and submitted to the lab. When photographing prints on hard flat surfaces the flash should be used as side lighting. Bullets and casings found at the crime scene can be positively matched back to a gun in the possession of a suspect.
Bullets and casings can also be examined at the crime lab and sometimes tell an investigator what make and model of weapons may have expended the casing or bullet. A bullet found at the crime scene can sometimes be matched back to the same lot of ammunition found in a suspect's possession. Tool marks can be positively matched to a tool in the suspect's possession. Firearm safety is a must at any crime scene. If a firearm must be moved at a crime scene, never move it by placing a pencil in the barrel or inside the trigger guard. Not only is this unsafe, but it could damage potential evidence. The firearm should be packaged in an envelope or paper bag separately from the ammunition and/or magazine. The ammunition and/or magazine should be placed in a paper envelope or bag. It is important that the ammunition found in the gun be submitted to the crime lab. Any boxes of similar ammunition found in a suspect's possession should also be placed in a paper container and sent to the crime lab. Casings and/or bullets found at the crime scene should be packaged separately and placed in paper envelopes or small cardboard
pillboxes. The legal issues surrounding physical evidence decides how a forensic team develops procedures for finding and collecting evidence at a crime scene to ensure that it is properly handled according to the type of evidence it is. Photographs and diagrams are a must no matter what type of evidence it is; safety of the field investigators is always the top priority. Proper collection techniques, chain of custody and proper analyzation of evidence is a must in order to make sure that it can pass the standards set forth by the courts for evidence. This ensures that once the evidence is presented to a jury, it presents the best roadmap of evidence showing how the crime was committed so that when they are deciding the fate of the suspect, they have all pertinent information before them showing the same conclusions that the investigators came to. Physical evidence is the only part of the picture involved in crime, and while it may not be a photograph of the suspects committing the crime, when linked with other information, possible witnesses, and expert testimony it is often instrumental in helping to paint an accurate portrait of what occurred.