Female DNA Found On Boston Bombing Explosives
The find is anything but conclusive though.
From the WSJ:
The genetic material could have come, for example, from a store clerk who handled materials used in the bombs or a stray hair that ended up in the bomb.
Which means it could be from someone they brushed up against on the way to the site, or from any number of interactions which took place during the period of assembly and placement of the bombs.
Regardless, authorities visited Tamerlan Tsarnaev's widow to gather some of her DNA, though the officials who talked with WSJ cannot confirm if she gave a sample or not.
Despite many reports flying around connecting the bombers to activities in the Caucases near Russia, investigators maintain they have no indication that anyone else aided in the planning or execution of the marathon bombing.
DNA is just one bit of forensics that can survive following an explosion.