(NBC News) - DNA found on a fragment of one of the Boston Marathon bombs does not match DNA taken earlier this week from Katherine Russell, the widow of the dead suspect in the attack, but she remains under scrutiny, investigators told NBC News.
Investigators said they still have many questions for Russell because they believe the bombs were assembled at the home she shared with her husband, Tamerlan Tsarnaev, who was killed in a firefight with suburban Boston police April 19.
Russell converted to Islam in 2009, after meeting Tsarnaev in a nightclub, and married him in 2010. She said through her lawyer that his alleged involvement in the attack came as an “absolute shock.”
Investigators said earlier this week that a piece of one of the pressure-cooker bombs set off by the brothers had a woman’s DNA on it, and that they wanted to determine who else might have handled the bombs.
Federal agents with bomb-sniffing dogs searched in Dartmouth, Mass., on Friday after people living there said they heard loud booms a month ago. The surviving suspect, Dzhokhar Tsarnaev, was a student at the University of Massachusetts-Dartmouth.
There was a similar claim from people living in the town of Hanover, about 25 miles south of Boston, but the police chief has said there was no connection to the marathon attack.
Authorities have released the body of Tamerlan Tsarnaev to a Worcester, Mass., funeral home. The director there, Peter Stefan, is known in Worcester as the man who buries those who die poor, unwanted or alone, The Worcester Telegram reported Friday.
Dzhokhar Tsarnaev has told investigators that the brothers planned to set off explosives on the Fourth of July but moved up their plans for Patriots Day and the marathon because they finished the bombs sooner than expected, investigators told NBC News on Thursday.