Students will describe techniques used to process a homicide crime scene and preserve the evidentiary value of the scene.

Describe how various medical forensics professionals process a crime scene. The crime scene encompasses all areas over which the victim(s), criminal(s), and witness(es) move during the commission of a crime If physical evidence is to be used effectively to aid in the investigation, it must first be recognized at the scene Objective 1

Responsibilities: Providing medical assistance Securing the area and establishing the perimeter Preserving fragile and transient evidence Extensive efforts must be made to exclude all unauthorized personnel from the scene - ropes - barricades - select positioning of officers as guards Every individual who enters the scene is a potential destroyer of evidence…..even individuals who are allowed to be there Obj. 1: Responding Officer

A CSI team will include a Photographer, a Sketcher and an Evidence Recorder/Recoverer/Custodian. It could be the same person as well. Sevens “S’s” of CSI: Secure the scene, Separate the witnesses, Scan the scene, See the scene, Sketch the scene, Search for evidence, Secure & collect evidence. Single investigators might use a grid, linear, or spiral pattern when searching for evidence. A group of investigators might use a linear, zone, or quadrant pattern. These patterns are systematic, ensuring that no area is left unsearched Obj. 1: Crime Scene Investigator

A Medical Examiner Crime Scene Investigator is only present when there is a deceased individual at the crime scene. He/She is only concerned with evidence that may assist in determining the cause of death of the individual They will: Obtain information Walk thru scene with lead detective Take photos with CSU team Examine the body Examine evidence and the rest of the scene Position of the body Look for the following: Clothing, Scars, Tattoos, Jewelry, Items in pockets Obj. 1: Medical Examiner

Identify how a crime scene and evidence may be compromised. The goal of crime scene investigation is to be able to collect evidence that will lead to the conviction of the criminal and to be able to reconstruct the crime scene with evidence to support. Any mistakes or lack of thoroughness can lead to evidence being missed at the crime scene or dismissed from court. Objective 2

Every individual who enters the scene is a potential destroyer of evidence…..even individuals who are allowed to be there. Special care must be taken to not contaminate a crime scene. Wear protective clothing: keeps the evidence off you and you from leaving hair & fibers, etc. in the scene. Cover your shoes & watch where you step. Survey the scene carefully and completely before removing any evidence. Only allow the individuals that HAVE to be there to enter the scene. Obj. 2: Contamination of a Crime Scene

If the chain of custody of evidence cannot be followed, it will not be allowed in court. 1.The evidence bag must be sealed with the signature of the collector across the seal. 2.The seal & signature is not broken or removed for processing. The next person to access the evidence must open the ‘bag’ away from the original seal. When finished, the person must complete the chain of custody paper within the ‘bag’ and reseal the ‘bag’ with their signature across the tape. This continues for each person who accesses the evidence. 3.Police stations, CSI offices, and forensic laboratories also keep a log of all evidence brought in, accessed or processed. Obj. 2: Chain of Custody

The weather can be very detrimental to evidence! Rain, wind, snow, heat, etc. can wash away evidence, such as footprints and can even ruin DNA. An outdoor crime scene will be covered if needed and if possible. Scenes where weather is a factor in collecting evidence are very difficult to process thoroughly, as time is vital to photograph and collect everything pertinant before it is ruined by the weather. Obj. 2: Environmental conditions

Forensic laboratory protocols must be followed PRECISELY in order to ensure the validity of the results, as well as to maintain the court value of the evidence. Any laboratory found to NOT be maintaining the correct procedures and protocols, brings into question not only the current cases, but ALL PREVIOUS cases that particular lab processed. Some laboratory specialists must certify in their field yearly to maintain their license. This means the evidence they process has valid results which are not contaminated or ‘created.’ Therefore, the evidence could hopefully solicit a confession from the suspect or it should hold up under the scrutiny of the defense in court. Obj. 2: Processing at the Lab

In the Amanda Knox trial, DNA evidence used to convict her was later part of the evidence used to set her free. The following link provides information about how the DNA evidence should not have been considered conclusive and how it may have been contaminated. flawed-say-dna-experts.html