DNA contamination is already turning out to be very widespread, we shed it everywhere, it lasts, and can get on victims' clothing, fingernails, etc.. Also contamination in labs.
Read recently about a case with apparently solid DNA evidence under victim's fingernails, supposed perp no real memory, but it turns out the police had him in custody at the time of the crime. He'd eaten in the same restaurant days earlier. I can't find the article quickly, but it was recent.
Read recently about a case with apparently solid DNA evidence under victim's fingernails, supposed perp no real memory, but it turns out the police had him in custody at the time of the crime. He'd eaten in the same restaurant days earlier. I can't find the article quickly, but it was recent.
Some others: https://newrepublic.com/article/123177/how-dna-evidence-incr...
https://www.theatlantic.com/magazine/archive/2016/06/a-reaso...
http://journals.plos.org/plosone/article?id=10.1371/journal....