Crime Scene Investigation Best Practices: Evidence Collection and Chain of Custody

1. Chapter 16 The Crime Scene, the Chain of Custody Requirement, and the Use of Fingerprints and Trace Evidence

2. The Crime scene • Chain of Custody • Fingerprints and Trace Evidence

3. Obtaining Evidence From a Crime Scene • When a crime occurs in a private premise such as a home, apartment, office, or factory, law enforcement officers most often enter with the consent of family and victims. • Law enforcement officers may stay in a crime scene for a reasonable period of time to perform whatever tasks they are obligated to do.

4. What can police search for in premises where a serious crime has recently occurred? • The court held in Mincey that law enforcement officers may make “warrantless entries and searches when they reasonably believe that a person within is in need of immediate aid” (emergency situations) • Law officers “may make a prompt warrantless search of the area to see if there are other victims or if a killer is still on the premises”

5. What can police search for in premises where a serious crime has recently occurred? (Cont.) • The police “may seize any evidence that is in plain view during the course of their legitimate emergency activities”

6. Courts do not require that police have any specific reason to fear a particular person remains inside the premises (e.g., U.S. v. Mata, 5th Cir. 2008). • But a sweep could be justified if it is known that a large amount of drugs has just entered the premises.

7. Obtaining Scent Evidence from the Crime Scene • Identification of a suspect may be made from clothing, blood, or bodily fluids found, and a tracking dog can be used to follow the scent of a suspect. • Scent evidence can be used, so a dog may: • 1. Follow the trail of a suspect from the crime scene

8. Using Scent Evidence, cont. • 2. Identify suspect in a scent lineup • 3. Place a suspect at or near the scene of the crime • 4. Establish probable cause for arrest or a search warrant • 5. Locate missing persons

9. Protecting and Searching a Crime Scene • The first officer to arrive at the scene of the crime automatically incurs the serious and critical responsibility of securing the crime scene from unauthorized intrusions. • To prove that evidence is genuine and authentic, and to show that the object is what is claimed to be, a witness would have to be able to:

10. Testify about where and how the object was obtained • Identify the object by a serial number if a serial number is on the object • Identify the object based upon personal knowledge and observations • “If the evidence is not readily identifiable or is susceptible to alteration by tampering, substitution, or contamination, the party must establish a chain of custody.”

11. The Chain of Custody Requirement • To use physical evidence in a criminal or civil trail, the party offering the evidence has the burden of proving that the evidence is genuine and authentic. • If the evidence (such as fingerprints or illegal drugs) could be subject to alteration by tampering, substitution, or contamination, a chain of custody must be shown.

12. The Chain of Custody Requirement (Cont.) • Chain of Custody: all persons who had possessions of the evidence must appear as witnesses to testify that the fingerprints or illegal drugs had not been tampered with, substituted, or contaminated while the witness had custody and control of the evidence.

13. Situations Not Requiring a Chain of Custody • A chain of custody is not required if the object to be used as evidence is not subject to alteration by tampering, substitution, or contamination.

14. The following cases are examples: • A chain of custody is not required in most shoplifting cases. • A pistol was held to be admissible without showing a chain of custody. • Twenty-two silver dollars stolen from a pawn shop were admitted for use in evidence although the victim couldn’t specifically identify them.

15. Fingerprints as Evidence • Latent fingerprints: Prints that are not visible, that are “processed” and then taken from a crime scene, can then be compared with fingerprints on file in local, state, or FBI files. • Fingerprints are perhaps the most common form of physical evidence, and certainly one of the most valuable. They relate directly to the ultimate objective of every criminal investigation: the identification of the offender.

16. Forged Identity • Due to forged identifications, law enforcement has increased security in identifying persons using their fingerprints. • Interpol, in 2008, reported that over 6 million passports have been lost or stolen in recent years.

17. Forged Identity (Cont.) • An equipment innovation in 2008 has made fingerprint analysis good for not only identifying a person, but determining if the person has touched drugs, explosives, poisons, or other substances.

18. Obtaining Fingerprints • Persons in a lawful police custody are routinely fingerprinted and photographed. Persons who have served in the military have their fingerprints on file, as do many government employees and people who receive licenses for such occupations as bartending driving a taxicab, working in private security, etc.

19. Proving That Fingerprints Were Impressed at the Time of the Crime • Fingerprints are circumstantial evidence from which inferences must be drawn. • It is impossible to determine how old a print is or when it was originally made. • As a general rule, the prosecution must first introduce fingerprint evidence by use of an expert witness and show a chain of custody to prove that the evidence is authentic, genuine, and has not been tampered with.

20. Proving That Fingerprints Were Impressed at the Time of the Crime • To prove that fingerprints were impressed at the time of the crime, the following evidence could be used:

21. Testimony of the victim or a witness that the defendant touched or handled the object on which the fingerprints were found. • Testimony that the surface had been washed or cleaned just prior to the crime • Fingerprints found in a home or an area to which the defendant did not have access to.

22. Trace evidence: The smallest things can make the biggest difference. • Trace evidence: most often applied to minute or microscopic bits of materials that are not immediately apparent to even a trained investigator.

23. Criminal crosses back porch, steps on brown paper bag • Criminal breaks a small glass pane on the back door • Struggles with homeowner

24. Obtaining Evidence by the Use of Tracking Devices • GPS (Global Positioning System) is being utilized more and more by law enforcement. • The Federal Rules of Procedures (2006) include tracking provisions such as: • A federal district court magistrate judge can issue an installation warrant. • The person or property to be tracked must be identified.

25. Tracking Devices (Cont.) • The courts have also held that the installation of a device in a public place does not require a warrant. • A warrant is necessary in a private place (such as a private garage).

26. Examples of Some Other Types of Evidence • Palm prints and lip prints • Footprints and shoe prints • Bite marks • Tire tracks