Bomb Reportedly Built in Tamerlan Tsarnaev's Home

Reinforcing the case that this was a home-grown effort

The bombs used in the Boston Marathon attack were built in the apartment that suspect Tamerlan Tsarnaev shared with his wife and child, a U.S. law enforcement official with first-hand knowledge of the investigation told CNN on Thursday. The official was not authorized to release the information.

Katherine Russell, Tsarnaev's widow, has remained largely out of view inside her parents' North Kingstown home since her husband's death.

It remains unclear what, if anything, Tamerlan's widow might have known or suspected, the source added.

According to her attorney, Amato DeLuca, the 24-year-old widow knew nothing of plans to bomb the race, and reports of her husband's involvement came as an "absolute shock" to Russell and her family.