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EQ: What is the process by which physical evidence is collected? Write the following questions: 1. What was the name of the missing teen? 2. What were the circumstances surrounding her disappearance? 3. Who is the lead suspect in this crime?.
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EQ: What is the process by which physical evidence is collected? Write the following questions:1. What was the name of the missing teen? 2. What were the circumstances surrounding her disappearance? 3. Who is the lead suspect in this crime? SEPTEMBER 24, 2012WARM-UP:STANDARD: SFS1c Determine the proper techniques to search, isolate, collect and record physical and trace evidence.
Forensic Sciencephysical evidence and the crime scenechapter 2
Any object that can establish that a crime has been committed or can link a crime and its victim or its perpetrator Presence must be recognized at the crime scene. Physical evidence
The first officer on the scene must obtain medical help for any injured parties and arrest the perpetrator, if possible. The crime scene must be isolated and protected as much as possible. Securing and isolating the crime scene
Unauthorized personnel should be kept away from the crime scene. The lead investigator must set the boundaries and determine the entry and exit pathways.
The crime scene needs to be permanently recorded in the original state. • Needed for future reference • Needed for court • 3 methods • 1. Photography • 2. Sketches • 3. Notes Record the scene
must be unaltered, objects cannot be moved • If something is removed from the scene, it is noted but is not reintroduced. • scene photographed as completely as possible, including surrounding areas, from all angles • physical evidence photographed to show location and position, close-ups taken to show detail, ruler can be added to show scale 1. photography
CrimeSceneInvestigation • PhotographingtheCrimeScene:
digital pictures can be altered, sometimes not acceptable in court, but can be joined to show 3D picture of scene Videotaping can be used in same manner of digital camera, can also capture narration of scene 1. PHOTOGRAPHY (CONT.)
Rough sketch • contains actual dimensions of the scene, accurate measurements made with tape measure • shows location of objects deemed of value to scene • basic diagram of scene • compass added to show north • legend or list of items added 2. sketches
Finished sketch Must contain information from rough sketch More precise, neater Can be made with computer 2. SKETCHES (CONT.)
Did you know... A cat’s urine glows under a blacklight? 111,111,111 x 111,111,111 = 12,345,678,987,654,321? Months that start with a Sunday will always have a Friday the 13th?
Must include detailed written description of the scene with the location of items of physical evidence recovered Must also identify the time an item was discovered, by whom, how and by whom it was packaged and marked, and the disposition of the item after it was collected 3. notes
May be only source of information when preparing for court case years later, should be very detailed Tape recordings and videotaping may be helpful at scene, used to make notes later 3. NOTES (CONT.)
Crime Scene Investigation • Uses and Information from Physical Evidence: Victim Suspect Physical Evidence Object Scene
After the lead detective does the preliminary walk-through, a more thorough search for physical evidence begins. Once found, evidence must be collected and stored in a way that preserves its integrity for forensic comparison and analysis. The chain of custody has to be maintained at all times. Dealing with physical evidence
One person should supervise and coordinate the collection of evidence. May divide the area into segments and collect evidence individually, or move from the outside in to the center. Conduct a systematic search for evidence
Search area must include probable points of entry and exit used by the criminals. What to search for will be determined by the nature of the crime. Evidence collector ensures that evidence is collected, packaged, marked, sealed, and preserved in a consistent manner
How many people supervise and coordinate the collection of evidence?
Take all clothing worn by participants in a crime. Each piece should be packaged carefully and separately. ITEMS OBTAINED FROM THE BODY & SENT TO THE LAB: 1. Victim’s Clothing 2. Fingernail Scrapings 3. Head and pubic hairs 4. Blood 5. Vaginal, anal, oral swabs (sex-related crimes) 6. Recovered bullets from the body 7. Hand swabs from shooting victims (gunshot residue analysis) Collect physical evidence
Critical areas of a crime should be vacuumed, and sweepings from different areas should be packaged separately. Fingernail scrapings should be taken from individuals who may have been in contact with other involved individuals.
Packaging • Forceps and similar tools may have to be used to pick up small items. • Unbreakable plastic pill bottles with pressure lids are excellent containers for hairs, glass, fibers, and various other kinds of small or trace evidence. THE CRIME SCENE
Manila envelopes,screw-cap glass vials, or cardboard pillboxes are adequate containers for most trace evidence encountered at crime sites. Ordinary mailing envelopes should not be used as evidence containers because powders and fine particles will leak out of their corners.
Packaging • Small amounts of trace evidence can also be conveniently packaged in a carefully folded paper, using what is known as a “druggist fold.” THE CRIME SCENE
If bloodstained materials are stored in airtight containers, moisture collecting inside cause the growth of mold, which can destroy the evidential value of blood. In these instances, wrapping paper, manila envelopes, or paper bags are recommended packaging materials.
Obtaining Reference Samples • Standard/Reference Sample—Physical evidence whose origin is known, such as blood or hair from a suspect, that can be compared to crime-scene evidence. • The examination of evidence, whether it is soil, blood, glass, hair, fibers, and so on, often requires comparison with a known standard/reference sample. THE CRIME SCENE
Although most investigators have little difficulty recognizing and collecting relevant crime-scene evidence, few seem aware of the necessity and importance of providing the crime lab with a thorough sampling of standard/reference materials.
Paper bags Wrapping paper, manilla envelopes, or paper bags Plastic pill bottles or druggist fold Air tight container Plastic pill bottles Sealed plastic bag
Today your group will create a crime scene story that takes place at a particular location. Create the story line using the following : Specific place w/in the location where crime took place Time crime took place Weapon used Were there any witnesses? If so who & how many? What evidence was found at the crime scene? Description of victim Point of entry and exit of the criminal(s) Possible motive-reason for the crime Sketch of the crime scene
