Eyewitnesses testimonies are extremely compelling forms of evidence. But, it’s not foolproof — just ask the 242 people mistakenly identified by eyewitnesses who served years in prison for crimes they did not commit until they were exonerated thanks to the introduction of DNA testing. A study gives new meaning to the notion of ‘guilt by association’ and shows how memory in humans as well as police use of mugshots and subtle innuendo can contaminate eyewitness testimonies.