Tsarnaev could also face state charges in the slaying of a Massachusetts Institute of Technology police officer, who was shot in his cruiser Thursday night on the MIT campus in Cambridge.
At the Massachusetts Institute of Technology, bagpipes wailed as students, faculty and staff members and throngs of law enforcement officials paid their respects to MIT police officer Sean Collier, who was ambushed in his cruiser three days after the bombing.
The attackers in the oil hub 155 miles north of Baghdad drove a minibus laden with explosives into the house of a local police chief and detonated an explosives-packed Toyota Land Cruiser outside the home of a leading member of the local Awakening Council, a group of Iraqis who have turned against extremists in the area.