SCI 114 – Scientific Principles of Forensic Science Page 1 Laboratory Exercise: Crime Scene Investigation Name: ____________________________________________ Date: _____________________ Section #: ________Introduction: Crime Scene Investigation1,2Crime-Scene Reconstructioninvolves forming a hypothesis of the sequence of events from before the crime was committed through its commission. The evidence is examined and compared with the witnesses’ statements to determine the reliability of their accounts. The investigator examines the evidence and attempts to determine how it fits into the overall crime scenario. The evidence does not lie, but it could be staged. It is important that investigators maintain an open mind as they examine all possibilities. A crime-scene investigation team consists of police officers, detectives, crime-scene investigators, medical examiners, and specialists. A crime-scene investigation consists of recognizing, documenting, and collecting evidence from the crime scene after the scene is secured. After walking through the crime scene in proper personal protective equipment (PPE) and identifying evidence, the crime-scene investigators document the scene by taking notes, photographs, and preparing sketches of the scene. A thorough examination of the crime scene should lead to a comprehensive collection of evidence. After careful examination of all the evidence, the crime scene investigation team should collect information helpful in solving the crime. Securing and Preserving the Crime Scene: The crime scene is secured by the first officers/investigators to arrive. Their job is to limit access to the crime scene and preserve the scene with minimal contamination. They have primary responsibility for: •Securing the safety of individuals at the scene; approach the scene cautiously (look, listen, smell) and determine if the site poses any danger. •Obtaining medical attention for anyone injured at the scene; call for medical personnel for the injured. •Calling in backup help, including medical personnel to help the injured and/or lab personnel. •Separating the witnesses so they may be interrogated separately to see if their stories are consistent. •Performing an initial walk-through of the area (scan the scene) to provide an overview of the crime scene. •Searching the scene briefly (scan the scene) to notify lab personnel what equipment is needed. •Collecting information, including the crime-scene address/location, time, date, type of call, and the names and addresses of all parties involved and present. •Securing the integrity of the scene by establishing the boundaries of the crime scene by setting up a physical barrier (tape) to keep unauthorized personnel (and animals, if present) out of the area •Protecting the crime scene by remaining alert and attentive. •Documenting the entry and exit of all authorized personnel.