The Boston Marathon bombing suspect was captured alive Friday night after police found him in a boat in a suburban backyard following a bloody rampage and daylong manhunt, law enforcement sources said.
Cheers went up from a crowd of police gathered at the scene in Watertown, Mass., where bursts of gunfire had been heard over the course of two hours.
The arrest ended five days of terror from the bombing at the marathon finish line, which killed three people, wounded 176 and left the city of Boston on edge.
It began unfolding soon after police told residents they could leave their homes even though suspect Dzhokhar Tsarnaev, 19, was still on the run.
Just before 7 p.m., an unsettling barrage of gunfire was heard on Franklin St. in Watertown, Mass., and dozens of police and armored vehicles sped to the area.
Officials said a woman in the area reported seeing blood leading to a boat in her yard, and thermal imaging from helicopters had located someone in the vessel.
A senior police official told NBC News the person was believed to be Tsarnaev, a naturalized U.S. citizen of Chechen origin who grew up in Cambridge after his family moved here a decade ago.
"Probably been there all day," the official said.
About an hour after the first barrage in Watertown, Mass., after night fell, more shots were heard. The police threw so-called flash-bang grenades designed to disorient and brought a negotiator to the scene.
The boat later caught fire.
The capture ended a manhunt that had the city of Boston and its suburbs on total lockdown -- following a rampage that included the slaying of a campus security officer, a carjacking and the death of Tsarnaev's 26-year-old brother, Tamerlan, in a firefight with cops.
The overnight violence had triggered an extraordinary shutdown of transportation, schools and businesses in Boston and its surrounding suburbs, with police warning more than a million people to hunker down behind locked doors while SWAT teams fanned out.
The brothers' bloody last stand began about five hours after the FBI released surveillance photos of two "extremely dangerous" men suspected of planting two bombs near the finish line of Monday's Boston Marathon, killing three and wounding 176.
Police are at the Cambridge, Massachusetts, home of the Boston Marathon bombing suspects, haven't yet entered the building, suspecting it may be booby-trapped. NBC's Ron Allen reports.
Tips about the identity of the suspects were still pouring in when the Tsarnaev brothers fatally shot Massachusetts Institute of Technology officer Sean Collier, 26, in his vehicle at 10:20 p.m., law enforcement officials said.
The brothers then carjacked a Mercedes SUV, holding the driver captive for a half-hour while they tried to use his cash card to get money from three ATM's, a source said. At the first, they put in the wrong number; at the second, they took out $800 and at the third, they were told they had exceeded the withdrawal limit, the source said.
The carjacking victim was released unharmed at a gas station in Cambridge, sources said. He told police the brothers said they were the marathon bombers and had just killed a campus officer.
As the duo sped in his car toward Watertown, a police chase ensued and they tossed explosive devices out the window, officials said.