WATERTOWN, Mass. (AP) — State police say officers are going door-to-door, but the Boston Marathon suspect is still on the loose.

Col. Timothy Alben of the Massachusetts State Police said Friday afternoon that officers would go street to street as the manhunt for the bombing suspect continues. Gov. Deval Patrick urged residents to continue staying indoors.

A pair of brothers is suspected of killing a Massachusetts Institute of Technology police officer late Thursday, then stealing a car at gunpoint.

The suspects' clashes with police began hours after the FBI released photos and videos of them. Monday's bombings killed three people and wounded more than 180 others.

Twenty-six-year-old Tamerlan Tsarnaev (tsahr-NY'-ev) was killed overnight. His 19-year-old brother, Dzhokhar (JOH'-kahr) is on the loose.