Investigators removed bags of evidence including some containing DNA samples from the Rhode Island home where the widow of suspected Boston Marathon bomber Tamerlan Tsarnaev has been living.
FBI agents spent hours Monday at the home of Katherine Russell's parents in North Kingstown, and came out carrying bags market DNA samples, a person familiar with the case said.
Investigators are hunting for evidence that suspects Tamerlan Tsarnaev, Russell's dead husband, and his younger brother Dzhokhar Tsarnaev made and set off two bombs at the finish line of the race two weeks ago.
The Wall Street Journal reported on Monday that investigators have found female DNA on at least one of the bombs used in the attacks.
The FBI declined to comment on the matter.
Police said the Tsarnaevs set off twin bombs on April 15 that ripped through the crowd watching the race on Boylston Street, killing three and injuring 264. The Tsarnaevs three days later led police in a wild car chase through metropolitan Boston, throwing grenades and exchanging gunfire as the officers closed in.
Russell, 24, said through her lawyer last week that she was doing everything she could to assist officials with the marathon bombing investigation.
Her lawyers have not said anything else, but a person familiar with the matter said the legal team has been negotiating how much access authorities will have to their client.
FBI agents have been seen at the Russell house and at her lawyer's office several times since she returned to Rhode Island from Massachusetts on Friday, April 19, after her husband was killed. On Monday afternoon she was seen leaving the house with her lawyers and was later seen leaving her lawyers' offices in Providence, Rhode Island.
Russell and Tamerlan Tsarnaev, 26, lived with their young daughter in Cambridge, Massachusetts. Police have said they found bomb material in that apartment.
Her lawyers have said she didn't know much about her husband's activities because she spent most of her time working as a health aide near Boston while he was home watching the child.
HUNTING BEYOND BOSTON AREA
Two law enforcement officials said both the FBI and local law enforcement agencies are now looking beyond the Boston area to try to identify associates or confederates of the Tsarnaev brothers.
The Wall Street Journal said officials familiar with the case cautioned that there could be multiple explanations for why the DNA of someone other than the two bombing suspects could be on remnants of the exploded devices. 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, the newspaper said.
Also on Monday, an autopsy on Tamerlan Tsarnaev determined precisely how he died after a bloody shootout with police but the results can't be made public until the body is claimed, a spokesman for the Massachusetts Medical Examiner said.
Authorities and the public have been waiting to learn whether Tsarnaev died in a hail of police bullets or when he was run over by Dzhokhar when the younger Tsarnaev fled in an SUV they had stolen.
Tamerlan Tsarnaev had stepped outside the SUV to shoot at police when he was hit by gunfire and was then run over by his brother when the younger Tsarnaev escaped. He was pronounced dead at Beth Israel Deaconess Medical Center.
"The Medical Examiner has determined the cause of death," said Terrel Harris, spokesman for the Massachusetts Office of the Chief Medical Examiner, but added that these findings will not be made public until the body is claimed and a death certificate is filed.
Russell would be permitted to claim the body from the medical examiner, the spokesman said.
Dzhokhar, 19, was captured on April 19 and has been recovering from bullet wounds at a prison medical center outside Boston.
The brothers' parents, now living in Russia, said on Sunday that they have abandoned initial plans to come to the United States to claim their older son's body and visit their younger son.
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