If triple killing had been solved, some say, Boston Marathon bombing could have been prevented

Nearly three years after three men were found dead in a suburban Boston home, their families are still waiting for authorities to say whether one of the Boston Marathon bombing suspects was involved.

Federal prosecutors in Boston revealed in court documents months ago that a friend of bombing suspect Tamerlan Tsarnaev (tsahr-NEYE'-ehv) told authorities they participated in the killings in Waltham (WAHL'-tham). But state investigators have not released any information.

That friend was shot and killed by an FBI agent last May in Florida after authorities say he charged at a Massachusetts trooper.

Tamerlan Tsarnaev was a friend of one of the slaying victims. He died following a gun battle with police several days after last year's bombing. His younger brother, Dzhokhar Tsarnaev (joh-HAHR' tsahr-NEYE'-ehv) is awaiting trial in the bombing.