UPDATE (8:54 p.m./ET): After a tense standoff at a Watertown home, the Boston Police are reporting that they have the second bombing suspect in custody. Live updates here.
UPDATE (3:01 p.m./ET): The massive manhunt for the second suspect in the Boston bombings is still underway. The FBI have released information about the suspect here. The city of Boston remains locked down as an "army of law enforcement officials" intensify their search operations for Dzhokar Tsarnaev, who escaped a shootout with police during violent overnight exchanges that killed his accomplice–and brother. CNN's This Just In blog has ongoing live updates here.
UPDATE (8:10 a.m./ET): CNN reports police sealed off densely populated portions of the Boston metro area this morning after a violent night chasing the Boston Marathon terror suspects left one of the men and a police officer dead. Federal, state and local law officers are swarming through the Boston suburb of Watertown, going door-to-door to track the second suspect down, said transit police spokesman Paul MacMillan. Police officers in full body armor, carrying automatic weapons, flooded the area. "This situation is grave." Massachusetts Police Col. Timothy Alben said. "This is a very serious situation that we are dealing with."
UPDATE: (April 19, 7:33 a.m./ET): The situation in Boston has erupted overnight. According to The Washington Post, police said one suspect is dead and a manhunt was underway for a second suspect after a police officer was killed at MIT and the suspects led police on a chase and into a violent confrontation involving explosions and gunfire in Watertown, Mass., about 10 miles west of Boston. The Associated Press reported the suspects were linked to the Boston Marathon bombings that killed three people and injured 176 near the race finish line Monday. For live updates, click here.
The FBI released photos and video of two men it called suspects in the deadly bombings at the Boston Marathon this afternoon and is asking for public help in identifying them.
The two men were photographed walking together near the finish line of the marathon before the explosions that killed three people and wounded about 180. One of the two men was seen setting down a backpack at the site of the second explosion "within minutes" of the blast, said Special Agent Rick DesLauriers, the head of the FBI's Boston office.
"Somebody out there knows these individuals as friends, neighbors, co-workers or family members of the suspects," DesLauriers said. "And though it may be difficult, the nation is counting on those with information to come forward and provide it to us."
For further info, see the FBI's web page devoted to the investigation–including more photos of the suspects–by clicking here. The FBI can be reached at 1-800-CALL-FBI (1-800-225-5324) with information.