Science never seems to prove as much as prosecutors claim. Case in point: fingerprints. Yes, prosecutors make some pretty ridiculous plea offers when they have incriminating fingerprints. They get that gleam in their eye, like “Guidry, you can’t get your client out of this one–I have fingerprints!!” Oh boy, I’ve never seen such a solid case. Wow, my client must really be guilty this time, right? Wrong.
What does it mean to say “the defendant’s fingerprints match those found at the crime scene?” Let me tell you what it’s not. When law enforcement testifies that a crime scene fingerprint “matches” the defendant’s fingerprint, they’re not saying that these two fingerprints are identical. Sure, it sounds that way, but even with two prints “matching”, the crime scene fingerprint could belong to someone else. Why, you ask? Because fingerprint analysis is not an exact science, it’s just a probability claim. Sure, all of science can be reduced to probabilities, but that’s a philosophical discussion for another day. Continue Reading