Boston bombing: Manhunt ends in a suburban backyard

Nikhil Kumar reports from the scene on the stroke of luck that led to the younger Tsarnaev brother finally being tracked down

Special Agent in Charge of the FBIís Boston Field Office Richard DesLauriers addresses the media during a news conference talking about the investigation of the Boston Marathon bombing (AP)

The chase ended because of a loose tarpaulin on a boat in the back garden of 67 Franklin Street.

Like the rest of the people who live in Watertown, a suburb of Boston on the north bank of the Charles river, David Henneberry and his family had spent Friday holed up inside their home as some 9,000 police officers, FBI agents, Swat-team members, National Guardsmen, agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives, and Homeland Security officials swept the streets for Dzhokhar Tsarnaev, a suspect in the Boston marathon bombings.

The 19-year-old had fled on foot following a high-speed car chase that ended with a shootout in Watertown in the early hours of Friday morning. The other suspect, his 26-year-old brother Tamerlan, had been killed in the shootout; doctors who pronounced him dead at the Beth Israel Deaconess Medical Center said his body was riddled with gunshot and blast wounds.

Earlier, the two suspects fatally shot an officer of the Massachusetts Institute of Technology campus police before stealing a car. They briefly held the driver hostage before releasing him 30 minutes later. Ed Deveau, the Watertown police chief, told CNN yesterday that the brothers had forced the hostage to withdraw money from an ATM before letting him go.

The Henneberrys had remained indoors as the search unfolded. Officers searched the area with guns drawn, as military helicopters hovered overhead. They climbed sheds and searched alleyways. Watertown was under siege. It was a weekday, but the streets were deserted, and at the eastern end of town, near the cordon at Mt Auburn Street and Kimball Road, only the Dunkin' Donuts and the 7-Eleven showed any lights. Just before dawn, the only customers were machine-gun-toting soldiers, police officers and assorted reporters who had been camped out next to the yellow police line.

The wider Boston metropolitan area was paralysed as public transport was suspended. Next door to Watertown, the bustling campus town of Cambridge, home to Harvard and MIT (and, it emerged, to the Tsarnaev apartment on the third floor of a wood-frame house on Norfolk Street), fell eerily silent as students retreated into their dorm rooms and apartments.

Mr Henneberry finally got the chance to get some air when, shortly after six in the evening, the authorities called off the lockdown. They had looked everywhere but the younger Tsarnaev had remained hidden. They weren't even sure if he was still in Watertown. They had patrolled 20 blocks and followed leads across the state. Black Hawk helicopters had reportedly landed on the roof of the University of Massachusetts Dartmouth, where he was enrolled as a student. Two days after the marathon bombings that left three dead and more than 170 injured, Tsarnaev was said to have appeared on campus. He worked out at the gym and slept in his dorm room, according to reports. A fellow student was quoted as saying that he'd seen the suspect at a campus party on Wednesday night.

But the leads proved fruitless. Timothy Alben of the Massachusetts State Police called for calm but conceded that one of the biggest manhunts in living memory had yielded no results. The state's Governor, Deval Patrick, asked residents to remain vigilant but to get on with their lives as the search continued.

When Mr Henneberry finally left his house, he noticed something odd: his boat, which was parked in the backyard for the winter, was covered by a tarpaulin that had survived the winter's wind, rain and snow – but it had now somehow come loose. It was a windy evening and the tarp was flapping.

He went to secure the covering, thinking that an animal must have forced its way inside the boat, snapping the straps. Sure enough, a strap was loose – but it hadn't snapped or been unhooked, according to his stepson, Robert Duffy. No: it had been cut, and it was stained with blood.

The boat was sitting on a raised towing platform. Mr Henneberry climbed a step ladder to have a look inside. Peering under the tarp he saw a pool of blood and something, or someone, curled into a ball inside the boat. Within minutes, he had dialled 911 and he and his family had been whisked away from the residence by officers. Barely an hour had gone by since the lockdown was lifted – and the missing suspect had been found.

The first sign of a new development came when gunshots were heard ringing out from the direction of Franklin Street. Suddenly, just as the crowd that had been camped out beyond the police lines began to disperse and residents began to step out of their homes for the first time since early on Friday morning, a group of officers could be seen heading in the direction of Franklin. It was soon closed off, and the boat was surrounded as the police waited for the arrival of bomb squad and Swat-team officers.

For a while it was not clear if the cornered individual was in fact the missing suspect. Throughout the investigation, there had been a number of false leads, something that reflected, in part, the speed at which events developed as investigators hunted down the perpetrators of the marathon attacks.

But it didn't take long for everyone in Watertown and beyond to realise that something serious was afoot. Later it was confirmed that the officers who surrounded the boat exchanged fire with the suspect. One report said a robot had been used to lift the tarp before officers finally apprehended Dzhokhar Tsarnaev. Stun grenades were used to disorient the suspect, as officers called out to him to give up. Ed Deveau of the Watertown police said yesterday that a negotiator had been positioned inside the house, on a floor overlooking the boat.

One of the first signs that the chase had ended came when some people – it wasn't clear if it was the officers or some residents, or both – began to applaud. Minutes later, however, numerous officers could be seen moving away from the scene and around three hours after the end of the lockdown, and almost 24 hours since the MIT police officer was shot, it became clear that the second suspect was alive and in custody.

The crowd cheered as police and FBI vehicles began to leave the scene, with many shouting out: "Thank you!" and "Good job!" There were cheers of "USA! USA!" as an ambulance, believed to be ferrying the suspect to a hospital, left Watertown.

The Boston police commissioner confirmed that the suspect was in a serious condition, with injuries that were thought to have been sustained during the chase late on Thursday and in the early hours of Friday morning. His brother was said to have been found with an explosive device, but there was no confirmation of this on Friday night.

"Boston police and state police and local police across the Commonwealth of Massachusetts responded with professionalism and bravery over five long days," President Obama said, speaking from the White House shortly after the hunt ended. "And tonight, because of their determined efforts, we've closed an important chapter in this tragedy."

Among those celebrating in Watertown last night was Kris Hagopian. He was walking his dog after finally being allowed into his home when the cordon was lifted. His family had spent the lockdown inside their house but he was stuck outside a few blocks away, having spent the evening before at his mother's house outside the closed-off area. "I'm just glad it's over," he said, as the relieved crowd continued to cheer and applaud.

Suspects on the run: How the net closed round the fugitives

Moments after investigators went before television cameras to broadcast photos of the two men in baseball caps wanted for the Boston Marathon bombing, queries from viewers started cascading in – 300,000 hits a minute, overwhelming the FBI's website. It marked a turning point in a search that, for all the intensity of its first 72 hours, had failed to locate the suspects. Experts say it instantly turned up already intense pressure on the two men to flee – increasing the chances they'd make mistakes that would lead to them being exposed.

The decision to ask the public for help was a gamble. Releasing the photos greatly increased the odds the two men would be recognised and turned in, even as it upped the chances they would try to vanish or commit more mayhem – exactly the scenario that has played out. Robert Taylor, a criminologist at the University of Texas at Dallas, who studies terrorism, said: "If you saw your face on TV and everywhere else as associated with the bombing... you would act irrationally, and that's exactly what they did."

The photo release instantly deprived the suspected bombers, Tamerlan Tsarnaev, 26, and his 19-year-old brother, Dzhokhar, of time, anonymity and options. The chaos of the subsequent pursuit contrasted sharply with the sweeping, methodical investigation that began after the Monday afternoon bombing. Dozens of investigators in white-hooded suits combed, catalogued and photographed evidence at the scene, even searching roofs to look for items blown into the air by the bombs' force.

Investigators gathered hours of video footage from security cameras near the bombing and appealed to the public to turn in their own video and photos. The investigation will probably collect about a million hours of video, said Gene Grindstaff, a scientist at Intergraph Corp, which makes video analysis software used by the FBI and other law enforcement agencies. This can spot patterns that humans might not notice, such as a car that turns up in different places, he said.

Mr Taylor added: "Here's the first thing that the computer was told: tell me if you can find the same people at both of those [bombing] locations." Additional parameters would narrow the search to, say, look for people carrying backpacks.

The process then required examination frame by frame, by the FBI's Operational Technology Division. By Thursday, once facial recognition software and agents had narrowed the search to images of two young men, investigators had to decide how to proceed.

The Tsarnaev brothers were already on edge. At a car body shop near their home, Dzhokhar had often stopped to talk with the owner Gilberto Junior about cars and football. But on Tuesday, the day after the bombing, he showed up biting his nails and trembling, Mr Junior said. The mechanic told Dzhokhar he hadn't had a chance to work on a Mercedes he'd dropped off for bumper work. "I don't care. I don't care. I need the car right now," Mr Junior said Dzhokhar told him.

By Thursday afternoon, the brothers had to know their options were narrowing fast. And then the FBI released their photos to millions around the world via newspapers, TV stations and websites. The time to move was now. "I think this developed rather quickly last night," said State Police Col Timothy Alben, late on Friday.

"I would wager that most of the activity that was printed in the media yesterday forced them to make decisions or take actions that ultimately revealed who they were." AP