Boston bombing suspect Dzhokhar Tsarnaev told authorities that his sister-in-law, Katherine Russell, "played no role in the April 15 blasts," a federal law enforcement official told NBC.
It was previously reported that Russell's DNA did not match the DNA found on fragments from one of the bombs. Russell is the widow of Dzhokhar Tsarnaev's brother and fellow bombing suspect, Tamerlan Tsarnaev.
The Associated Press reported on Saturday that Russell is under close watch by federal authorities. The scrutiny comes as authorities hope not only to to determine whether Russell shares blame for the bombing, but also "to push for as much information as possible regarding whether the bombing suspects had ties to a terrorism network or accomplices working domestically or abroad," legal experts told the AP.
Russell's lawyers said their client knew nothing about the attack, according to the Associated Press.
"It seems to me they don't believe her yet," David Zlotnick, a professor of law at Roger Williams University, said.
The April bombing killed three and injured more than 260.