[jansan]

Do people know about the Phantom of Heilbronn? For 15 years, police in Germany found DNA of one and the same person on about 40 different crime scenes. The crimes seemed to be completely unrelated, including murder, burglary, theft and even disputes between neighbors. This person was labeled "The Phantom" and all that was known aws that she was a female (XX chromosme type female). Everyone agreed that she must have been a true monster.

To keep it short, it was all a contamination of the swabs used by forensics. The DNA belonged to a worker in a factory where the swabs were produced. It took the police 15 years to find out. 15 years!

I sometimes wonder what would have happened if that woman had by accident become a suspect in a crime and her DNA run through the police's DNA database.

https://de.wikipedia.org/wiki/Heilbronner_Phantom

[dekhn]

Much of science involves the eliminate of false positives (this is a great example).

Throughout my career as scientist (I'm an ex-scientist now) and machine learning, I came to the conclusion that false positive rates must be kept extremely low for people to trust the system, because of the consequence of false positives.