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The Crime Scene

The Crime Scene

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The Crime Scene

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  1. The Crime Scene Coach Whitaker

  2. Vocabulary • Crime Scene—any place where evidence may be located to help explain events • Modus Operandi—the characteristic method of operation of a criminal • Chain of Custody—a written record of all people who have had possession of an item of evidence • Alibi—statement of where a suspect was at the time of a crime.

  3. Vocabulary • Accomplice—person associated with someone suspected of committing a crime • Suspect—person thought to be capable of committing a crime • Secondary Crime Scene—an alternate location where additional evidence may be found • Primary Crime Scene—the original location of a crime or accident

  4. Crime Scene What evidence can be found at a crime scene? Brainstorm with your group to come up with a list of evidence you might find at a crime scene. What is the difference in a primary and secondary crime scene? Name some potential primary and secondary crime scenes in the following scenes-------bank robbery, burglary, murder, theft, assaults.

  5. At the Crime Scene • Forensic Science Begins at the Crime Scene which can provide useful information that must be carefully, systemically, scientifically, and legally collected • The information and evidence at the scene that must be used later to reconstruct the scene and events that led up to the crime • It establishes the MO and the motive for the crime

  6. At the Crime Scene • The main reason to carefully analyze the crime scene is to learn what happened and to gather evidence to convict the suspect • The CSI’s experience, knowledge, and capabilities are critical for deciding which items at a scene are actual evidence • If errors at made at the scene in protecting, processing, and analyzing the evidence it can be thrown out in court

  7. Steps in Handling the Crime Scene • Preserving and Isolating the Crime Scene • Observing and Documenting the scene • Searching the scene for evidence • Collecting and packaging evidence • Maintaining Chain of Custody

  8. Crime Scene Personnel • POLICE OFFICERS are 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. • The CSI UNIT documents the crime scene in detail and collects any physical evidence. • The District Attorney is often present to help determine if any search warrants are required to proceed and obtains those warrants from a judge. • The MEDICAL EXAMINER (if a homicide) may or may not be present to determine a preliminary cause of death. • SPECIALISTS (entomologists, forensic scientists, forensic psychologists) may be called in if the evidence requires expert analysis. • DETECTIVES interview witnesses and consult with the CSI unit. They investigate the crime by following leads provided by witnesses and physical evidence.

  9. Preserving and Isolating the Crime Scene • The first officer on scene determines the nature of the crime and has the following responsibilities: • Get medical assistance if needed (saving lives is the first priority even if it means disturbing the crime scene) • Make an arrest • The scene must be secured and protected against any unauthorized person from entering it • Suspects and witnesses must be detained • Protect and preserve evidence at the scene

  10. Preserving and Isolating the Crime Scene • The investigator interviews the first responder, victim, or witnesses to learn what may have happened • Police officers note and record details such as weather conditions, odors, lights, signs or prior activities at the scene, etc

  11. Activity • Forensic Science on the Net Name ___________________________ • CHIN – Interactive Investigator • http://www.virtualmuseum.ca/Exhibitions/Myst/en/game/index.phtml • PDF Worksheet http://sciencespot.net/Pages/classforsci.html

  12. Observing and Documenting the Scene • The investigator should do the following: • Examine the scene to get an overall view to find pieces of evidence • To ID the points of entry and exit • To consider what may have happened • To mentally outline how the scene should be handled KEEN OBSERVATION AND DETAILED NOTES ARE CRITICAL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  13. Observing and Documenting the Scene • Notes—the most important parts of processing the scene. Why? • Forces investigators to more observant (makes you focus on details you would miss or overlook) • Notes should be complete and written clearly and legibly • They should detail step by step every action that the investigator takes in the order it happened

  14. Observing and Documenting the Scene • Notes should include: • Date and time • Location, environment, weather description • Description of the scene • Written description of physical evidence, location, time of discovery, and packaging • Names of the people involved

  15. Observing and Documenting the Scene • Photographs “A picture is worth a thousand words” Before making any detailed examination or touching the scene, an investigator must photograph the scene • Pictures help CSI remember details, show where evidence was placed in the scene, and help jury and judge visualize the scene

  16. Observing and Documenting the Scene • The investigator must include photos that: • Clarify the scene • Close up of evidence • Views of the witness • Location and surroundings of the crime • Objects from different angles • Rule to scale • Are documented for evidence

  17. Observing and Documenting the Scene • Videotaping • The investigator can narrate relevant information while moving through the scene

  18. Observing and Documenting the Scene • Sketches • Sketches give photographs perspective • Gives a permanent record of the relationships of different points of interest to each other in the scene • Gives a better layout • The sketch must have measurements, scale, and correct placement of details • Combines note with photos

  19. Activity • Sketches, Photos, and videotaping • http://sciencespot.net/Pages/classforsci.html Investigation Discovery (PDF) AT  

  20. Searching the Scene for Evidence • Without evidence even the most heinous crimes will go unpunished • The care that is taken collected evidence directly impacts the police ability to prosecute crimes • Evidence can be damaged, contaminated, or even lost which makes it useless to the crime lab and inadmissible in court

  21. Searching the Scene for Evidence • The first step is finding it by taking an orderly approach to search the scene • Many items will be visible while others are not • The way investigators search the scene depends on the size and physical layout of the area in question

  22. Searching the Scene for Evidence • Searchers usually following a geometric pattern, some examples include: Grid Search

  23. Searching the Scene for Evidence • Linear Search

  24. Searching the Scene for Evidence • Quadrant or Zone

  25. Searching the Scene for Evidence • Spiral Search

  26. Search Activity • Search Using different stories, crimes, and scenes • (Courtyard)

  27. Gathering the Evidence • The next step is collect and package the evidence • The investigator must put each item in a separate container and label it • When collecting evidence, investigators start with evidence that is fragile or that is likely to be lost, damaged, or contaminated, such as blood, fibers, hair, fingerprints, shoeprints, and tire tracks

  28. Gathering the Evidence • Generally, pill bottles, vials, manila envelopes, and plastic bags are good container for most evidence • Special considerations include: • Wet items must be dried before packaging • Containers must be sealed to prevent leaks or breakage • Biological items should be dried and kept in a freezer

  29. Gathering the Evidence • Clothing with trace evidence should be packaged carefully to avoid disturbance • Firearms should be fixed rigidly inside a wooden container • A collection may be made using adhesive tape

  30. Gathering the Evidence • Gathering delicate evidence • Fingerprints are photographed and then lifted or transferred to a material • Tool marks and shoeprints or tire impressions are photographed before being lifted or casted • Fibers and hair are searched for with alternative light sources and picked up with tweezers • Carpets and furniture are vacuumed with a clean bag for each area

  31. Control Samples • Control Samples are samples with a know origin. For example, blood from a scene compared to the blood of the victim • These control samples must be collected and compared with samples from the scene • All evidence should be sealed with tamper proof tape and properly labeled

  32. Gathering Evidence Activity • Search Using different stories, crimes, and scenes • (Courtyard) • Collect Evidence and Package • List for each crime

  33. Chain of Custody • There must be a written record of who has had possession of the evidence at all times • The court needs to know who has been responsible for evidence from the time it was collected to time it appears in court

  34. Chain of Custody • The record will show: • Who collected the evidence • Who had contact with the evidence • At what time • Under what circumstances • And if changes where made to the evidence

  35. Chain of Custody • The record is usually on the package itself • It is not uncommon for everyone who came into contact with the evidence to testify in court

  36. Chain of Custody • After the scene has been processed and investigated, evidence is sent to the forensic lab or stored

  37. Unit Project • Crime Scene Processing Project Elements • (three scenes) (2 Groups) • Secure scene • Invent own crime • Notes, photographs or videos, sketches, search, evidence gathering and packaging, and Chain of Custody • Photostory or Movie maker about crime

  38. Checklist for finding five pieces of evidence, chain of custody, Crime scene log, • Draw a detailed sketch with notes