Erin E. Murphy in The New Republic:
In 2009, a horrific murder occurred in a place rarely associated with violence: a Yale graduate scientific laboratory. On what was to be her wedding day, a graduate student’s body was found head down within a small mechanical chase behind a wall in the laboratory. As she fell, her underwear snagged and entangled on a vent pipe that spanned the length of the chase. Extensive DNA samples were taken from the victim, her clothing, and spaces around the chase. Testing revealed two profiles, one of which matched a co-worker later implicated in the crime through other evidence. But a second person’s DNA was also found, ominously recovered in significant quantities from samples that included the waistband of the victim’s underwear. When the profile was submitted to the DNA database, a match returned the name of a convicted offender living nearby.
Further investigation, however, turned up something mysterious. The database match suspect had died two years prior to the Yale attack. Stumped, investigators first ruled out an identical twin or other relative, as well as laboratory contamination errors.