#2. The Man Whose DNA Linked Him to a Crime in a Country He'd Never Been To
Nicolas Loran/Photos.com, kalawin jongpo/Photos.com
DNA matching, as it turns out, is far from perfect. British barkeeper Peter Hamkin learned that the hard way when Italian police hauled him into jail on suspicion of murder. After requesting a search of the British DNA database, they had found that Hamkin's was a match for evidence found at the scene, which was baffling because Hamkin was in Liverpool at the time of the murder, and, in fact, had never been to Italy.
But nobody from Italy could commit murder!
After 20 days in jail, a second, more exhaustive DNA test showed that he was innocent. The problem is that DNA tests, contrary to what you might think, don't match an entire DNA strand up with one in the database (because DNA is mindbogglingly complicated). Instead, they just look for a set number of matches, or "loci." In the U.S. and U.K., 13 loci are considered a match. In other countries, the number is 10. But, because of incompatibilities in the way different police departments do the test, the European-wide database that fingered Hamkin only looks at 6. With those odds, you might wind up falsely accusing a gorilla.
Actually, you're probably safe accusing most gorillas of murder.
The FBI claims that the U.S. standard of 13 loci gives 1 in 113 billion odds of a false match. But before you stop being paranoid, you should listen to Arizona state crime lab analyst Kathryn Troyer. While doing a search, she came across two felons with very similar profiles. Normally one would assume the felons were close relatives. But they were of different races, so that was unlikely. This led her to see how many other close matches there might be, and terrifyingly, she found dozens.
"I don't want to turn this into a whole racial thing, but I really don't think I have the same DNA as you, Jerry."
By the way, fingerprint matching works similarly: Entire prints aren't matched; rather, a certain small number of similar points constitutes a "match." How often does that lead to false positives? No one knows for sure, but some experts think it might be 0.8 percent of all of them -- which would be 1,900 people each year.
But even when there is an exact DNA match, you can still wind up with cases like this next one ...
#1. A Bone Marrow Transplant Gives a Man a Rapist's DNA
An Alaskan man was accused of rape, once again based on DNA evidence extracted from the scene of the crime. The case would have been open and shut if not for one technicality -- the accused man was already in prison at the time. That's generally about as tight an alibi as you can hope for, unless you're engaged in some kind of Shawshank Redemption scenario where Andy happens to be a rapist.
Castle Rock Entertainment
"You what? That's it, you can go find yourself another golden-voiced prison buddy."
After some careful detective work to figure out how this guy was phantom-molesting people from his prison cell, they finally found the answer -- he'd previously received a bone marrow transplant from his brother, and the brother had committed the crime. The marrow transplant literally meant that his brother's DNA was floating around in his blood.
Of course, blood testing isn't the only way to match your DNA to a crime scene, and it's been noted that this whole mess would never have happened if they'd used the more common method of a mouth swab. But then, scientists have also discovered that, after you kiss someone, their DNA actually winds up in your mouth and hangs around in there, so keep that in mind before making out with any potential ax murderers.
We don't judge. Just brush your teeth afterward.
Luckily, donating your blood marrow in an attempt to get away with a crime is probably too painful and complex a scheme for villains to attempt outside of a comic book.
Evan V. Symon is a Moderator in the Cracked Workshop. When he isn't being tried for a crime a one-armed man did, he can be found on Facebook and be sure to bookshelf and vote for his new book The End of the Line.
Related Reading: There's no better example of "mistaken identity" than being confused for a god- and this article is full of people who found themselves in that situation. Of course, the most common cases of mistaken identity occur in music. If you think Bob Marley wrote "Don't Worry, Be Happy" then you're as wrong as his dreadlocks were lice-ridden. If you're up for something more sinister, we have stories of intentional identity theft too.