The 19-year-old surviving suspect of the Boston bombings, Dzhokhar Tsarnaev, has been found hiding in a boat propped up in a suburban back garden.
Not far from the scene of the police shootout in Watertown that killed his older brother Tamerlan, the teenager was discovered wounded and taken to hospital after a shootout that lasted around an hour. Police have said he is in a "serious condition" after suffering significant blood loss.
Police were tipped off after the boat's owner noticed blood stains around the craft, and having lifted the tarpaulin to investigate, found Dzhokhar sheltering within.
Officers threw stun grenades into the boat to disorientate the suspect and prevent him from escaping, as FBI and police helicopters flew overheard and SWAT teams stood close by.
"CAPTURED!!!" tweeted the Boston Police Department. "The hunt is over. The search is done. The terror is over. And justice has won. Suspect in custody."
The streets of Watertown erupted in cheers, as news came through that the suspect had been captured alive, according to HuffPost reporters Christina Wilkie and Michael McLaughlin.
Many still want to know why the two brothers carried out the attacks, which injured more than 180 people and killed eight-year-old Martin Richard, Krystle Campbell, 29, and a Chinese graduate student, named in reports as Lu Lingzi.
In a statement at the White House, President Obama said: "Tonight our nation is in debt to the people of Boston and the people of Massachusetts. All in all, it has been a tough week, but we've seen the character of our country once more."
He also echoed the questions many have been asking in the wake of the attacks, adding: "Why did young men who grew up and studied here as part of our communities and our country resort to this violence?"
The two suspects are sons of Chechen refugees from southern Russia, and moved to the US in 2001, from Russian republic of Dagestan.
The mother of Tamerlan and Dzhokhar gave an interview to Russia Today, claiming the FBI had been in contact with Tamarlan Tsarnaev for between three and five years."
Boston had been in lockdown after the shooting of Massachusetts Institute of Technology police officer Sean Collier, in Watertown earlier that day.
After the shooting, the two suspects hijacked a Mercedes SUV at gunpoint, then drove for half an hour with the owner of the vehicle held hostage. The owner was able to flee at a petrol station close by.
There was then an exchange of gunfire as the suspects threw improvised devices at police from their vehicle and Tamerlan was wounded and later died in hospital.
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The Boston marathon bombs were made from ordinary kitchen pressure cookers packed with metal and ball bearings. Investigators suspect the devices were then hidden in duffel bags and left on the ground.
They exploded within 15 seconds of each other near the finishing line as thousands of runners were pouring in.
The Boston Marathon is one of the world's oldest and most prestigious with about 23,000 runners taking part, including hundreds from the UK and Ireland.