1. 1 Collecting and Preserving Evidence Maintaining the integrity of evidence

2. 2 Introduction to Forensic Science and the Law Transient evidence-temporary evidence, easily changed or lost (odors, temperature, impressions) Conditional evidence-produced by a specific action or event at the crime scene which must be observed and recorded (forced entry, signs of struggle) Types evidence

3. 3 Introduction to Forensic Science and the Law Associative Evidence-evidence that links a suspect to a crime scene (blood, shoeprint, fingerprint) Reconstructive evidence-any evidence that helps to reconstruct what happens at the crime scene (blood spatter, broken windows, pried doors, etc) Demonstrative evidence-any visual aid (charts, graphs, sketches etc) used to make evidence easier to understand Types evidence

4. 4 Introduction to Forensic Science and the Law Who is authorized to collect evidence?  Police, criminalists, and Coroner’s technicians are charged with locating, protecting, and transporting evidence to the crime lab or coroner’s office. The coroner and crime lab technicians analyze each piece of evidence. Collecting evidence

5. 5 Introduction to Forensic Science and the Law Criminalist-A criminalist is a person with a background in science, typically having at least a baccalaureate degree in an area such as chemistry, biology, forensic science, or criminalistics. additional training given by his/her employer (either a government or private laboratory) allows a criminalist to apply scientific methods and techniques to examine and analyze evidentiary items and testify in court as to his or her findings. Collecting evidence

6. 6 Introduction to Forensic Science and the Law Each step (from collection to analysis and interpretation) must be done properly and with great attention to detail, or the evidence may be deemed inadmissible in court. For direct evidence Miranda Right-must be read to suspects before they can be questioned. Collecting evidence

7. 7 Introduction to Forensic Science and the Law Evidence must be located before it can be collected. locating evidence for collection without a search warrant occur in cases when police, or emergency personnel are called to the scene of a crime. If the probable location of the evidence is not associated with the crime scene, then a search warrant must be obtained. Collecting evidence-Evidence location

8. 8 Introduction to Forensic Science and the Law Exclusionary Rule: evidence acquired illegally, such as collected from a person’s home without a warrant, can’t be used in court. Note: It doesn’t try to suggest the evidence is less true or reliable for having been collected illegally, it’s only meant to deter police and the government from invading homes without warrants and risking the consequences to get evidence. Collecting evidence-ignoring proper protocol

9. 9 Introduction to Forensic Science and the Law Fruit of the Poisonous Tree Doctrine: This is an extension of the exclusionary rule, where any evidence discovered because of illegally obtained evidence is also excluded. Collecting evidence-ignoring proper protocol

10. 10 Introduction to Forensic Science and the Law How it applies: To a Crime scene investigator or forensic scientist, this just means you have to be sure you have authorization to collect evidence before you do so. For instance, if investigating arson, the fire department is called in to deal with the fire, and can collect any evidence they find, but they can’t go back once there’s no danger without a search warrant.. Collecting evidence-ignoring proper protocol

11. 11 Introduction to Forensic Science and the Law Emergency situations: situations where someone’s life or health is in danger. Any evidence found during this emergency entry may be used Police or other emergency personnel cannot make an emergency entrance, leave and then return at a later date to search for evidence without a warrant. Collecting evidence-searching without a warrant

12. 12 Introduction to Forensic Science and the Law Immediate Loss of Evidence- case where suspect or other agents such as fire is threatening to destroy evidence. Lawful arrest: any property (vehicle, home, etc) that is in the immediate control may be searched for evidence. Consented Search: person consents to search of his/her person or property. Collecting evidence-searching without a warrant

13. 13 Introduction to Forensic Science and the Law Fourth amendment protects citizens against “unreasonable search and seizures” Police and crime scene investigators need to obtain search warrant from a judge Only law enforcement officers may obtain a search warrant; attorneys, private investigators and private citizens cannot obtain a search warrant. Collecting evidence- Executing a search warrant

14. 14 Introduction to Forensic Science and the Law In order for a warrant to be issued the following requirements must be met: 1.Probable cause: cannot be just a hunch or gut feeling Must be suspicion of illegal activity supported by evidence Information obtained from a reliable informant Collecting evidence- Executing a search warrant

15. 15 Introduction to Forensic Science and the Law 2. Specificity of the search: must state exactly what police are looking for. 3. Area of search: The area to be searched must be explicitly stated. Note: This can be very tricky, because if the warrant states that officers will be searching the house, any garage or shed is off limits. Collecting evidence- Executing a search warrant

16. 16 Introduction to Forensic Science and the Law Protecting the evidence begins with the “ SEVEN S’s OF CRIME-SCENE INVESTIGATION” 1.Securing the scene is the responsibility of the first-responding police officer (first responder). The safety of all individuals in the area is the first priority. Preservation of evidence is the second priority. Protecting the evidence

17. 17 Introduction to Forensic Science and the Law Protecting the evidence begins with the “ SEVEN S’s OF CRIME-SCENE INVESTIGATION” The officer protects the area within which the crime occurred, restricting all unauthorized persons from entering. Transfer, loss, or contamination of evidence can occur if the area is left unsecured The first officer has to keep a security log of anyone who visit the crime scene. Protecting the evidence

18. 18 Introduction to Forensic Science and the Law Protecting the evidence begins with the “ SEVEN S’s OF CRIME-SCENE INVESTIGATION” 1. Securing the scene-Setting up a perimeter to prevent unauthorized persons from entering and contaminating 2. Separating the witnesses: This done to prevent witnesses from working together to create a story (collusion) 3. Scanning the scene: A preliminary survey of the scene needs to be done to see where photos need to be taken or to determine if there is a primary and secondary crime scene Protecting the evidence

19. 19 Introduction to Forensic Science and the Law Protecting the evidence begins with the “ SEVEN S’s OF CRIME-SCENE INVESTIGATION” 4. Seeing the Scene: Crime scene examiner needs take a view of the crime scene from several angles 5. Sketching the scene: An accurate rough sketch of the scene includes-position of the body (if there is one), and any other evidence. Protecting the evidence

20. 20 Introduction to Forensic Science and the Law Protecting the evidence begins with the “ SEVEN S’s OF CRIME-SCENE INVESTIGATION” 6. Searching for evidence: Based on location, and number of investigators, any of the following search method may be used-spiral, grid, linear, or quadrant. 7. Securing and collecting evidence: Evidence must be properly packaged, sealed and labeled and the chain of custody must be maintained. Protecting the evidence

21. 21 Introduction to Forensic Science and the Law Gathering evidence is not a haphazard process, rather, there is an order to gathering evidence The first evidence searched for and collected is the most fragile, most likely to be lost, damaged, or contaminated. Each piece of evidence must be packaged separately in order to avoid damage and cross contamination. We will explore this topic in greater detail Gathering the evidence

22. 22 Introduction to Forensic Science and the Law Evidence from suspected arson should be collected and placed in an air tight container Biological items should be dried and kept frozen Broken glass should be packaged in a corrugated container such as a cardboard box Trace evidence such as hair or fiber should apply the use of a bindle or “druggist” fold. We will explore this topic in greater detail Gathering the evidence

23. 23 Introduction to Forensic Science and the Law Chain of custody: the documented and unbroken transfer of evidence The chain of custody requirement is based on the idea that if evidence is left unsupervised after collection, someone can tamper with it and it’s no longer reliable and therefore inadmissible. Preserving the integrity of the evidence

24. 24 Introduction to Forensic Science and the Law evidence gets a form attached during collection that anyone who takes custody must fill out with information describing what the item is, who collected or handled it, when it was collected, where it was collected, why was it collected, and an accompanying signature Preserving the integrity of the evidence

25. 25 Introduction to Forensic Science and the Law Preserving the integrity of the evidence

26. 26 Introduction to Forensic Science and the Law Further exploration of chain of custody Analyzing and interpreting evidence class vs Individual evidence Questioned vs Known sample control sample Individualizing evidence Increasing probative value of class evidence. Next topic