Investigators have found female DNA on a fragment from one of the two bombs used in the attack on the Boston Marathon two weeks ago, according to a U.S. official briefed on the probe.
The genetic material may have come from a number of sources and its discovery doesn’t necessarily mean that additional people were involved beyond the two brothers suspected in the bombing, said the official, who asked not to be identified in discussing an open case.
The DNA find emerged as authorities continue to investigate whether the suspects, Tamerlan and Dzhokhar Tsarnaev, had help in planning or carrying out the April 15 attack. So far, according to a second U.S. official who asked not to be identified, there’s no evidence of such assistance.
Among those under scrutiny is Tamerlan’s wife, Katherine Russell Tsarnaev. Agents from the Federal Bureau of Investigation visited her parents’ home in North Kingstown, Rhode Island, yesterday and took a DNA sample from her, according to one of the U.S. officials briefed on the probe.
Amato DeLuca, a lawyer for Katherine Tsarnaev, said in an e-mail yesterday that she was continuing to “assist in the investigation in any way she can.” Last week, he said in an interview that she knew nothing about the attacks beforehand and “was as shocked as anybody” when they happened.
Jason Pack, an FBI spokesman, declined to say whether Katherine Tsarnaev was cooperating voluntarily and said that the bureau can’t discuss specific aspects of the case.
Tamerlan Tsarnaev was killed in a police shootout April 19. He and his brother are suspected by U.S. authorities of setting off the bombs at the Boston Marathon finish line that killed three people and wounded 260.
Dzhokhar Tsarnaev, 19, was apprehended on April 19 after a manhunt that paralyzed the Boston metropolitan area. He was found hiding in a boat in the backyard of a Watertown, Massachusetts, home and taken to the hospital for treatment of gunshot wounds.
The younger Tsarnaev, now being held at a federal prison west of Boston for inmates needing medical care, is charged with using and conspiring to use a weapon of mass destruction.
As part of the investigation, the FBI wants to interview family members including the suspects’ parents, who are in Russia, said an official familiar with the probe who asked not to be identified. Friends, associates and others who were part of the suspects’ lives are also being sought for interviews, the official said.
‘Up Our Game’
In the aftermath of the attack, members of Congress said investigators have told them that the Tsarnaev brothers were schooled in radical Islam and terrorist bomb-making online.
Lawmakers say they want to know why U.S. intelligence and law enforcement agencies didn’t take a closer look at Tamerlan when he traveled to Russia last year. The trip took place after Russian authorities raised concerns in 2011 with their U.S. counterparts that he might be involved in extremist activities.
“We’re going to have to up our game,” Senator Lindsey Graham, a South Carolina Republican, said on CBS’s “Face the Nation” broadcast on April 28. “How could you miss the fact that the guy you were -- you were informed by a foreign intelligence service you have a radical in your midst.”
The FBI, at the request of Russia’s domestic intelligence service, conducted a three-month review of Tamerlan Tsarnaev’s activities in 2011. The FBI checked the tip thoroughly “and did not find terrorist activity, domestic or foreign,” White House spokesman Jay Carney said on April 22.
Russia declined to cooperate when the FBI sought more specific information, according to Representative Mike Rogers, a Michigan Republican and chairman of the House Intelligence Committee.
The Russians’ warning to the U.S. about Tamerlan in 2011 stemmed from two secretly recorded phone calls between him and his mother, according to a U.S. official who asked not to be identified because of the continuing investigation. Russian authorities didn’t tell that to the U.S. until after the bombing, the official said.
President Barack Obama in a telephone call yesterday thanked President Vladimir Putin for Russia’s “close cooperation” in the case. The two also discussed security for the 2014 Olympics in Sochi, Russia, according to a White House statement.