Chapter 5

Fingerprints: Your Personal Signature


Bullet Defining fingerprints

Bullet Classifying and matching prints

Bullet Exposing and collecting prints

If you read, watch TV, or go to the movies, you know that fingerprints play a vital role in many mysteries, whether real-life or fictional. Fingerprints often are how police identify criminals and solve crimes, even crimes that are decades old.

Although fingerprint identification is now standard practice, acceptance of the individuality of fingerprints by police, scientists, and the courts didn’t happen overnight.

In this chapter, I explain the science behind fingerprinting, a little bit of its history, and some of the methods used for finding and lifting prints at the crime scene.

Getting a Grip on Fingerprints

Using a bright light and magnifying glass, take a close look at your finger pads (the fleshy surface of your fingers that you use for touching and gripping). You’ll see very fine lines that curve, circle, and arch. These lines are composed of narrow valleys called grooves and hills known as friction ridges. When you see an inked fingerprint, you’re looking at the pattern made by the friction ridges.

Friction ridges give ...

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