1. 1 Book Cover Here Copyright © 2014, Elsevier Inc. All Rights Reserved Chapter 3 THE CRIME SCENE Discovery, Preservation, Collection, and Transmission of Evidence Criminal Investigation: A Method for Reconstructing the Past, 7 th Edition

2. 2 Copyright © 2014, Elsevier Inc. All Rights Reserved The Crime Scene Defining the Limits of the Crime Scene The Crime Scene as an Evidence Source – The CSI Effect Opportunity for Discovery Purpose of Search Arrival of the First Police Officer Arrival of the Investigator Other Sources of Physical Evidence

3. 3 Copyright © 2014, Elsevier Inc. All Rights Reserved The Crime Scene as an Evidence Source 1. An offender brings physical evidence to the crime scene a. Tools, weapons, flammable fluid, hard drives, messages on cell phones, etc. 2. An offender may leave evidence behind a. Fingerprints, tool marks, shoe prints, bullets, blood-spatter patterns, etc. 3. Some evidence is unavoidably left behind a. Ransom notes, recorded tapes, etc. 4. Investigator’s observations and interviews might develop intangible evidence.

4. 4 Copyright © 2014, Elsevier Inc. All Rights Reserved The CSI Effect From a forensic scientist’s perspective, CSI shows have been both meaningful and detrimental

5. 5 Copyright © 2014, Elsevier Inc. All Rights Reserved Search Warrants Exceptions allowed by the Court – Consent to search Must be given voluntarily by a person reasonably believed to have control over and legal access to the premises – Emergency situations: Those involving an attempt or opportunity to carry off or destroy evidence. To support this contention, belief must meet the standard of probable cause. Those involving threats to safety or life. In these cases, a lower level of proof — reasonable suspicion — is acceptable.

6. 6 Copyright © 2014, Elsevier Inc. All Rights Reserved Discovery of Physical Evidence Overview, Walk-Through, and Search Recording Conditions and Evidence Found – Notes – Videography – Photographs – Sketches (Computer Aided Design – CAD – systems) Collection and Preservation – Preservation: Legal Requirements Identification Continuity of Possession/Chain of Custody

7. 7 Copyright © 2014, Elsevier Inc. All Rights Reserved Trace Evidence Differs from ordinary physical evidence mainly because of its small size; calls for special methods Three techniques: – Vacuuming – Shaking – Sweeping and adhesion to tape

8. 8 Copyright © 2014, Elsevier Inc. All Rights Reserved Preservation — Legal Requirements Certainty of the identification Continuity of possession — the chain of custody of each item of evidence

9. 9 Copyright © 2014, Elsevier Inc. All Rights Reserved Preservation and Collection Preservation – Scientific Requirements & Means Collection – Scientific Requirements & Means – Scientific Requirements – Control of Variables Background Material Sample Sufficiency Means Tools Containers

10. 10 Copyright © 2014, Elsevier Inc. All Rights Reserved Collection – Special Considerations Trace Evidence AIDS and Hepatitis C

11. 11 Copyright © 2014, Elsevier Inc. All Rights Reserved Transmission of Evidence to the Laboratory Best done in person for legal and scientific reasons In the case that this is not possible, the U.S. Postal Service or UPS Must be packaged properly Special concerns in high-profile cases

12. 12 Copyright © 2014, Elsevier Inc. All Rights Reserved Finding Physical Evidence by Canvassing Interviewing neighbors or companions of suspects – May produce writing samples, trace evidence, or DNA samples from where suspect visited

13. 13 Copyright © 2014, Elsevier Inc. All Rights Reserved Conclusion The crime scene is a critical component of the investigation Do not ignore contribution of patrol officers and first responders Knowledge of crime scene activities is an important aspect of the investigative function