tailieunhanh - Lecture Criminal investigation - Chapter 3: Physical evidence

A common theme in all criminal investigations, and one of the most important throughout this text, is the collection of physical evidence. While the topic of physical evidence is addressed in several chapters of this lecture, the chapter specifically focuses on the techniques used to identify, collect, package, and store particular types of physical evidence for subsequent examination. | THREE Physical Evidence LEARNING OBJECTIVES Distinguish between class and individual characteristics. Outline procedures for locating and handling soil and pollen evidence. Understand processes for preserving footwear and tire prints and impressions. Summarize techniques for collecting glass and paint evidence. Discuss methods of collecting and storing fibers, cloth fragments, and impressions. Understand how to locate, identify, and use tools to obtain fingerprints. Describe the importance of forensic dentistry. Discuss the identification and analysis of bloodstains. Identify the determinations that can be made from firearm evidence. Outline techniques for identifying questioned documents. 3-1 THE CRIME SCENE Defines the location at which an offense was committed Search the crime scene for physical evidence Includes a wider area that contains the lines of approach and, Flight by the perpetrator The crime scene includes setting of the crime and its general environs 3-2 CLASS AND INDIVIDUAL CHARACTERISTIC EVIDENCE Class: a group of objects or persons with characteristic physical evidence common to it Examples include soil and hair Individual characteristics can be identified as having originated with a particular person or source Establishes individuality Examples include fingerprints and footprints 3-3 LOCATING AND HANDLING SOIL EVIDENCE Soil evidence is important when the suspect drives/walks on unpaved areas It is picked up by: tire treads shoe bottoms pants cuffs It may also be located in: subject's vehicle articles in a suspect's trunk 3-4 PRESERVING FOOTWEAR AND TIRE PRINTS AND IMPRESSIONS Footwear prints and impressions should be photographed: As part of the general scene Also photograph with a scale Dental Stone is used in casting impressions 3-5 FOOTWEAR IMPRESSIONS Photographs of footwear impressions at a crime scene In the first photo only the impressions are shown In a subsequent photo a ruler will be added to show sizes Later casts will be made of the . | THREE Physical Evidence LEARNING OBJECTIVES Distinguish between class and individual characteristics. Outline procedures for locating and handling soil and pollen evidence. Understand processes for preserving footwear and tire prints and impressions. Summarize techniques for collecting glass and paint evidence. Discuss methods of collecting and storing fibers, cloth fragments, and impressions. Understand how to locate, identify, and use tools to obtain fingerprints. Describe the importance of forensic dentistry. Discuss the identification and analysis of bloodstains. Identify the determinations that can be made from firearm evidence. Outline techniques for identifying questioned documents. 3-1 THE CRIME SCENE Defines the location at which an offense was committed Search the crime scene for physical evidence Includes a wider area that contains the lines of approach and, Flight by the perpetrator The crime scene includes setting of the crime and its general environs 3-2 CLASS AND .