Investigative Processes Lesson PDF

qJust as a car needs fuel to run, criminal laboratories also need EVIDENCE to run. qEvidence can be what MAKES or BREAKS a criminal case. qEvidence can be used to convict, exonerate or prove a defendant to be not guilty of an accused crime. qBefore evidence can be used, its presence must...

qJust as a car needs fuel to run, criminal laboratories also need EVIDENCE to run. qEvidence can be what MAKES or BREAKS a criminal case. qEvidence can be used to convict, exonerate or prove a defendant to be not guilty of an accused crime. qBefore evidence can be used, its presence must be recognized at the crime scene. qForensic science begins at the crime scene. qIf the investigator cannot recognize evidence, or cannot properly preserve it for laboratory examination, it is of no use. qWith proper training, police agencies and investigators can ensure competent performance at crime scenes. Who is at the crime scene? First responders (law enforcement, paramedics, fire fighters) Crime scene investigators (document scene in detail and collect evidence) Medical examiners & coroner (aka: coroners determine COD) Detectives (look for leads/interview witnesses/work collaboratively with CSI) Specialists (entomologists, psychologists, anthropologists, sketch artists, etc.) qInvestigators are trained to follow certain steps to ensure that evidence is found, secured, and collected so that it maintains its integrity as it travels from the crime scene to the court room. qThe chronological documentation or paper trail that records the sequence of custody, control, transfer, analysis, and disposition of physical or electronic evidence is known as the chain of custody. qThere are 7 overall steps to crime scene investigation. qSo, what are the steps that crime scene investigators follow? ü Securing the Scene ü Separating Witnesses ü Scanning the Scene ü Seeing the Scene ü Sketching the Scene ü Searching the Scene ü Securing and Collecting Evidence qToday, you will participate in a jigsaw activity, where you will research one of the 7 steps of CSI. qAs you research, your goal is to become an “expert” on this topic. qYou will then be placed in a group where you will teach the other members of the group about your step. Ø Group 1: Securing the Scene Ø Group 2: Separating Witnesses Ø Group 3: Scanning the Scene Ø Group 4: Seeing the Scene Ø Group 5: Sketching the Scene Ø Group 6: Searching the Scene Ø Group 7: Securing and Collecting Evidence qSECURING THE CRIME SCENE The first officer arriving on the scene of a crime must preserve and protect the area as much as possible. However, priority should be given to obtaining medical assistance for individuals in need AND to arresting the perpetrator. Once everyone is safe, extensive efforts must be made to exclude all unauthorized persons from the scene. Ropes or barricades along with strategic positioning of guards will prevent unauthorized access to the scene. qSECURING THE CRIME SCENE Every individual who enters the scene must be documented (crime scene logs) as well as the time and date that they entered and exited the scene. qSEPARATING THE WITNESSES Separating the witnesses is the next priority. Witnesses must not be allowed to talk to one another. Investigators will compare their accounts. Witnesses are separated to avoid working together as well as to avoid one witness to be influenced by another. The following are questions that are usually asked of the witnesses: What did you see? Where were you when you made this observation? Did you see anyone else? Do you have any information that may be helpful in our investigation? qSCANNING THE CRIME SCENE Next, investigators and first responding officers will do a quick scan of the scene and will mark evidence with evidence markers. A more thorough search is done later. The purpose of this step is to allow records of the scene to be made quickly and efficiently. qSEEING THE CRIME SCENE During this step, a trained forensic photographer photographs the evidence that has been marked. Any time new evidence is marked, photographs will be made. We will look at the procedures for taking photographs at a crime scene later. qSKETCHING THE SCENE Once photographs have been taken, the crime scene investigator will sketch the scene. This is a rough sketch that depicts the dimensions of the scene and shows the location of all evidence. The sketch should match the photographs and evidence markers in the sketch should align with evidence markers in the photographs. We will also look more deeply at crime scene sketches in a later lesson. qSEARCHING THE SCENE During this step, investigators really focus on finding all evidence and a more detailed search is performed. A search pattern is declared, and investigators work together to ensure that no part of the crime scene has been left unsearched. If new evidence is found, it is marked with evidence markers, photographed and documented in the sketch. We will also look more deeply into search patterns at a later date. qSECURING AND COLLECTING EVIDENCE Physical evidence can be anything from massive objects to microscopic traces. Each piece of evidence (no matter how big or small) must be preserved in its original state (as much as possible) and its integrity maintained. Each item should be handled carefully and wrapped separately to avoid cross contamination. The search for evidence is not limited to the crime scene (ex. Evidence can be found on the body during an autopsy). qSECURING AND COLLECTING EVIDENCE Investigators must handle and process evidence in a way that prevents any change from taking place from the crime scene to the crime lab. The use of disposable gloves is vital during handling of evidence. Evidence should remain unmoved until investigators have documented its location and appearance in notes, sketches and photographs. Crime scene investigators have a large assortment of packaging materials and tools, ready to package a diverse array of evidence. qSECURING AND COLLECTING EVIDENCE The chain of custody is the process of protecting evidence from the crime scene to the lab. According to the chain of custody, evidence should be packaged in the following way: Appropriate packaging should be used. Packaging should be sealed with evidence tape. The signature of the collecting officer should appear on the evidence tape. The seal must never be broken. If evidence must be processed, the evidence must be removed without puncturing the signed evidence label. A chain of custody log must be filled out. The signatures on the log must match the signatures on the evidence labels. qSECURING AND COLLECTING EVIDENCE Evidence tape must be signed. Chain of Custody log must travel with evidence and should reflect anyone who had contact with evidence. qSECURING AND COLLECTING EVIDENCE In the event that evidence is found that is REALLY tiny, investigators will use a bindle to secure the evidence. Sometimes referred to as a druggist’s fold, a bindle ensures that evidence isn’t lost. Packaging Evidence qNEXT STEPS q Once evidence is collected, it can be transferred to a crime lab for further analysis. q However, each person that handles the evidence must be included on the chain of custody log. q They must also place the evidence in a new package with a new evidence seal, so that the integrity of the evidence is maintained. q Failure to do so will result in the inadmissibility of the evidence in court. qPractice q Complete the Securing and Packaging Evidence Close Reading Assignment.