Citing "officials familiar with the case," the Journal emphasizes that "there could be multiple explanations for why the DNA of someone other than the two bombing suspects" was uncovered that would not necessarily indicate complicity in the attack. For example, CBS notes, the DNA might conceivably have come from "a marathon spectator or a clerk who sold" materials that were ultimately used in the making of the bomb.
The only current suspects in the bombing, which killed three people and injured 260, are Tamerlan and Dzhokhar Tsarnaev. Tamerlan was killed during a shootout with police on April 19. Dzkhokhar was arrested later that day. Investigators last week found no evidence of additional accomplices in the bombing, based on a "preliminary examination of the cellphones and computers" belonging to the brothers. However, police have not ruled out the possibility of an accomplice, and have not yet determined whether or not the DNA discovery indicates a woman's involvement in the attack.
Authorities have visited Tamerlan's widow, Katherine Russell, an FBI spokesman confirmed Monday, and did collect a DNA sample. However, Russell has not been charged with involvement in the bombing, and is not a suspect at this time.