This story in the paper yesterday caught my attention. It's about a burglar in Germany who has been identified by the distinctive earprint he has allegedly left behind when pressing it against doors to see if anyone is at home.
Like a lot of these internet stories that do the rounds, it contains enough specifics that it might be a true story, or could just be the figment of a lazy journo's imagination. This article quotes Hamburg police spokeswoman Ulrike Sweden about the case. As unlikely as the name sounds, she does exist and does work for the Hamburg Polizei.
Earprint matching is a branch of science that I never knew existed, but there seems to be quite a body of scholarly research about it; from Meijerman, Thean and Maat's Interpretation of Earprints to renowned Dutch expert Cornelis Van Der Lugt's chapter on the subject in Forensic Human Identification. Databases of thousands of earprints have been compiled, and (its proponents say) no two are the same.
Police Inspector Van Der Lugt describes in his potted history of forensic ear comparison that the first recorded use of ear identification evidence in Britain was in 1910. Later, American doctors conducted research into ear comparison as an aid to preventing babies being mixed up in hospitals. Van Der Lugt asserts that an earprint was first used to identify a burglar in Switzerland as far back as 1965.
In 1998, a man in the UK was convicted of murdering an elderly woman in Huddersfield after the prosecution showed that ear prints on a newly washed window could only have been left by him as he listened for signs of movement inside the house, according to the BBC. But he successfully appealed the conviction, and was acquitted at his retrial after the Crown led no evidence.
Some respected experts doubt the reliability of ear comparison, noting that an ear can change shape depending on the temperature or how hard it is being pressed to a surface. The strengths and weaknesses of this kind of evidence were discussed in R v Mark Dallagher  EWCA Crim 1903.