The sample wasn't a match with DNA found at any known crime scene. But it was close. Someone related to the donor had left DNA on the bodies of two prostitutes slain in the 1990s.
That nugget of information gave investigators the opening they needed to follow a trail of other genetic clues, in trash bags, coffee cups and cigarette butts, that ultimately led them to the donor's brother, John Bittrolff.
"This was inadvertent," Suffolk County prosecutor Robert Biancavilla said of the initial partial DNA match that led to the arrest. "The fish just happened to jump in the boat."
New York's Division of Criminal Justice Services says the clue was one of more than 1,450 investigative leads that have been developed as a result of the state's decision in 2012 to collect DNA samples from all criminal convicts, no matter how minor their offenses.
More From This Section
Eight state labs now create the profiles and compare genetic material to try and solve crimes.
The expanded sampling "clearly has been a success," said Richard Aborn, head of the Citizens Crime Commission in New York City. "It's another example of how technology and science can be a crime-fighting tool."
The trail that police said led to Bittrolff began with a sample submitted by his brother, Timothy Bittrolff, following his misdemeanor conviction for violating an order of protection in 2013.
Investigators then set up a camera outside John Bittrolff's home in Manorville. When he left nine bags of trash outside, they swooped in.
DNA was retrieved from a plastic cup in the trash, and found to be a match with the material found on the slain women. Bittrolff was arrested and when he sipped from a coffee cup during questioning, authorities got another sample of his DNA. That sample also matched the crime scene evidence.