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.

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.