Boston bombing: One suspect dead, another on the run

A police chase and shootout ended with one suspect dead, and another on the run, according to Boston Police commissioner Ed Davis.

Federal agents swarmed neighboring Watertown after local police were involved in a car chase and shootout with at least one of the suspects. During the pursuit, officers could be heard on police radio traffic describing the suspects as having grenades and other explosives.

As one escaped and one was shot and killed by police. A man was seen sprawling on the ground, though it is unclear if that was the person killed by police.

The FBI has yet to publicly confirm a connection between the events in Watertown and the twin explosions that killed 3 people and injured 170 others at the Boston Marathon.

"We are aware of the law enforcement activity in the greater Boston area," according to Boston FBI spokesman Greg Comcowich.

Residents of Watertown, a suburb 10 miles from Boston, were ordered to stay in their respective places.

The Watertown shootout occurred after a gunfight erupted at the Massachusetts Institute of Technology, where a police officer was shot and pronounced dead. The campus was placed on lockdown for several hours, and students were told to remain indoors.

"Residents in and around Watertown should stay in their residences," the alert read. "Do NOT answer door unless it is an identified police officer."