The Crime Scene

How Are Your Observation Skills? This activity demonstrates our ability to remember details accurately. Testimony about personal experience is frequently used during an investigation. How accurately do people remember what they have seen? What factors may play a role in what we can remember and describe about something we have witnessed? Consider these questions as you do the following activity.

Directions: Observe the picture for exactly 30 seconds. Look at everything you think might be important. After 30 seconds, answer the questions How observant were you? Compare your answers to the picture. READY

Questions What time was it on the clock? How many people were in the scene? How many males? females? Describe the person at the front of the line. Was it a man or a woman? Was he or she wearing a hat? What kind of clothes was the person wearing? Could you tell how tall the person was? Did he or she have any distinguishing features? What day of the month was it? Did you notice anything unusual in the picture?

Did you know? Eyewitness misidentification is the single greatest cause of wrongful convictions nationwide, playing a role in more than 75% of conviction overturned through DNA testing Still, the criminal justice system relies on eyewitness identification and testimony for investigating and prosecuting crimes

Crime Scene Vocabulary Crime Scene: Any physical location in which a crime has occurred or is suspected of having occurred Primary Crime Scene: The original location of a crime or accident

Vocabulary cont…. Suspect: Person thought to be capable of committing a crime Accomplice: Person associated with someone suspected of committing a crime Alibi: Statement of where a suspect was at the time of a crime Physical Evidence: Encompasses any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or crime and its perpetrator

Approaching a crime scene First priority should be given to obtaining medical assistance for individuals in need of it and to arresting the perpetrator Personal safety and the well being of victims Preserve and isolate the crime scene Record the crime scene

Crime scene personnel Police officers Typically the first to arrive at a crime scene They are responsible for securing the scene so no evidence is destroyed and detaining persons of interest in the crime

Personnel cont…. CSI unit Documents the crime scene in detail and collects any physical evidence

Personnel cont…. District attorney Often present to help determine if any search warrants are required to proceed and obtains those warrants from a judge

Personnel cont…. Medical examiner (if a homicide) may or may not be present to determine a preliminary cause of death

Personnel cont…. Detectives Interview witnesses and consult with the CSI unit Investigate the crime by following leads provided by the witnesses and physical evidence

Crime Scene Protocol Step 1: Interview Step 2: Examine The first step in investigating a crime scene is to interview the first officer at the scene or the victim to determine what allegedly happened, what crime took place, and how was the crime committed. This information may not be factual information but it will give the investigators a place to start. Step 2: Examine The second step in the investigation of a crime scene, which will help identify possible evidence, identify the point of entry and point of exit, and outline the general layout of the crime scene. Step 3: Document The third step in the protocol involves creating a pictorial record of the scene as well as a rough sketch to demonstrate the layout of the crime scene and to identify the exact position of the deceased victim or other evidence within the crime scene. Step 4: Process The crime scene technician will process the crime scene for evidence, both physical and testimonial evidence. It is the crime scene technicians responsibility to identify, evaluate and collect physical evidence from the crime scene for further analysis by a crime laboratory.

Recording the crime scene….Photographs Evidence Multiple views Entrances Exits Windows Close ups Perspectives Multiple angles

Recording the crime scene….Sketch A draft representation of all essential information and measurements at a crime scene It shows all recovered items of physical evidence, as well as other important features of the crime scene

Recording the crime scene….Notes Record of actual measurements of the scene, evidence and the relationship between them Match to sketch Use a key

Collecting Evidence Bag and Tag Victims clothing Fingernail scrapings Head and pubic hairs Blood Hydrocarbons (arson) Recovered bullets from the body and/or surrounding area Hand swabs or washings from shooting victims

Documentation…Chain of custody Description of item Location in crime scene from which collected Case number Date/time collected Signature of collector They must identify The time an item was discovered By whom How and whom it was packaged and marked

Rules for evidence collection Maintain the physical integrity of a sample Limit degradation (the act of degrading) Prevent contamination Chain of custody

The Seven S’s of Crime Scene Investigation Secure the scene Separate the witnesses Scan the scene Seeing the scene Sketch the scene Search for evidence Secure the collected evidence

Forensic science services Forensic pathology Involves the investigation of unnatural, unexplained or violent deaths Charged with determining the cause of death May conduct autopsy which is a medical dissection and examination of a body in order to determine the cause of death

Forensic science services…cont Forensic anthropology Concerned with the identification and examination of human skeletal remains

Forensic science services…cont Forensic entomology The study of insects and their relation to a criminal investigation, commonly used to estimate time of death

Stages of death Rigor mortis Results in the shortening of muscle tissue and the stiffening of body parts in the position at death (occurs in the first 24 hours and disappears within 36 hours) Livor mortis Results in the settling of blood in areas of the body closest to the ground (begins immediately on death and continues up to 12 hours) Algor mortis Results in the loss of heat by the body (general rule..the body loses heat by 1 to 1 ½ degrees Fahrenheit per hour until the body reaches the environmental temperature)