NEW YORK (AP) — A puzzling DNA match that appeared to link the 2004 killing of a New York City drama student and evidence collected this year from a protest affiliated with Occupy Wall Street was instead the result of a lab worker who handled both cases, a law enforcement official said Wednesday.

A database of DNA samples recently matched DNA on a metal chain collected after the protest this spring to material on a CD player found eight years ago near Sarah Fox’s body. But during the process of excluding people who may have handled evidence, it was determined the DNA came from a lab worker who dealt with both cases, said the official, who spoke to The Associated Press on condition of anonymity because the investigation was ongoing. It was not clear if the mistake was the result of contaminated evidence.