BOSTON - Officials say one of the bombs used in the Boston Marathon had female DNA on it.
The FBI has now taken a DNA sample from one of the suspect's widow.
FBI agents went to the Rhode Island home of Tamerlan Tsarnaev's widow Katherine Russell.
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Officials say they will compare her DNA to evidence on a bomb fragment.
Agents are also trying to see if Tamerlan was in contact with a Canadian Jihadist in Russia, before the militant was killed by Russian troops last year.