Testing alibis is not as straightforward as it seems

IN 1985 RONALD COTTON, a resident of North Carolina, was falsely convicted of rape and burglary, and sentenced to life imprisonment. Nearly a decade later, he was exonerated on the basis of evidence. Not only did the victim make an error in identifying him as the perpetrator, but Mr Cotton had also provided an alibi that could not be corroborated.This, it turned out, was because he was wrong about where he had been when the crime was committed. A subsequent investigation showed that he had, in error, instead told the police where he was at that time on the same day during the week before. An unfortunate confusion, then, with serious consequences. But, if research just published in is to be believed, one that might be commoner than imagined.