Police captured a 19-year-old ethnic Chechen suspected of carrying out the Boston Marathon bombings with his older brother after an intense day-long manhunt on Friday that closed down the city and turned a working-class suburb into a virtual armed camp.

The break in the case sent waves of relief and jubilation through Boston and the suburb of Watertown, where armored vehicles roamed the streets and helicopters flew overhead through the day. Residents and police officers cheered and clapped when the suspect, Dzhokhar Tsarnaev, was caught after an exchange of gunfire with police.

A Massachusetts State Police spokesman said Tsarnaev was bleeding and in serious condition in a Boston hospital. He had been hiding in the stern of a boat parked in the backyard of a house in Watertown, police said. A resident called police after seeing blood on the boat.

President Barack Obama told reporters at the White House after the suspect’s capture that questions remained from the bombings, including whether the two suspects received any help. Monday’s bombing has been described by Obama as "an act of terrorism.” It was the worst such attack on U.S. soil since the plane hijackings of Sept. 11, 2001, and set nerves on edge across the United States with a series of security scares.

The Boston Police Department said in a message on Twitter: "CAPTURED!!! The hunt is over. The search is done. The terror is over. And justice has won. Suspect in custody.”

Tsarnaev is one of two brothers believed to have set off bombs made in pressure cookers and packed with ball bearings and nails at the finish line of the world-famous event, killing three people and injuring 176. The family of Martin Richard, an 8-year-old boy killed in the blast, cheered his capture. "Tonight, our community is once again safe from these two men,” the family said in a statement.

The older brother, Tamerlan Tsarnaev, 26, was killed on Thursday night in a shootout with police less than a mile from where Friday night’s capture took place. The FBI had publicized pictures of the two men on Thursday and asked the public for help in identifying them.

Hours after the photos were released, a furious sequence of events erupted, including the fatal shooting of a police officer on the campus of the Massachusetts Institute of Technology. The night culminated in a firefight in Watertown during which police say the brothers threw bombs at officers. Tamerlan suffered fatal wounds, while the younger brother escaped on foot.

The brothers had not been under surveillance as possible militants, U.S. government officials said. But the FBI said in a statement on Friday that in 2011 it interviewed Tamerlan at the request of a foreign government, which it did not identify.

"The request stated that it was based on information that he was a follower of radical Islam and a strong believer, and that he had changed drastically since 2010 as he prepared to leave the United States for travel to the country’s region to join unspecified underground groups,” the FBI statement said. The matter was closed because interviews with Tamerlan and family members "did not find any terrorism activity, domestic or foreign.”

Agencies