Forensics For Dummies, 2nd Edition

Chapter 17

Picking Apart Trace Evidence

IN THIS CHAPTER

Establishing the value of trace evidence

Checking out some useful microscopic and analytical instruments

Understanding how trace evidence works

Criminals are clever. At least, they think they are. They know to wear masks and use the dark of night to avoid being identified by any witnesses. They’ve seen in movies the importance of wearing gloves or wiping away fingerprints. They know not to leave behind their own blood because DNA can hang you. Yet they continue to be tracked down, arrested, and convicted as the direct result of tiny bits of evidence — evidence perpetrators don’t see or realize they’re leaving behind or carrying away from the crime scene on shoes and clothing. As the saying goes, “The devil’s in the details.” So is the evidence.

Defining Trace Evidence

From the hair that falls off your head to the carpet fibers that you track in on the soles of your shoes, trace evidence is any very small physical material that can be transferred from person to person or between a person and a crime scene. Hair, fibers, pieces ...