A police helicopter circled overhead. The sky buzzed and blue lights flashed from the ground on the campus of Massachusetts Institute of Technology at about 11pm on Thursday night. This marked the start of a dramatic 36 hours in the hunt for the perpetrators of the Boston Marathon bombings.
At 5.10pm on Thursday the FBI had released photographs and videos of two suspects that investigators believe were behind the two bomb blasts near the finish line of the marathon last Monday. The blasts killed three people and injured more than 170 in the most devastating attack on the mainland United States since 2001.
FBI chief Rick DesLauriers, in a major breakthrough in the case, asked the public for help in trying to identify the men photographed carrying backpacks through marathon spectators before the bomb blasts. He warned members of the public not to approach them; they were considered “armed and extremely dangerous”.
Five hours later, at about 10.20pm, a robbery took place at a 7-Eleven shop, triggering a series of events that turned the manhunt for the bombers into a car chase across suburbs of Boston and a frenzied gun battle.
Police officer shot dead
Ten minutes after the robbery a campus police officer was found shot dead at the Massachusetts Institute of Technology, across the Charles River from the Back Bay area of the city where the marathon bombings took place. The area around Vassar and Main Streets was cordoned off and police checked nearby hedges and the roadsides using a sniffer dog.
The police officer was later named as Sean Collier (26), who had previously been an information technology employee at the Somerville Police Department before moving to MIT police, where he had worked for just over a year.
He was shot multiple times in an assassination-style killing in his car after he responded to a report of a disturbance. He was transported to Massachusetts General Hospital and later pronounced dead.
Around midnight police started picking up reports of an armed car-jacking by two men around Third Street in Cambridge. The two men, who had been in a Honda car, seized a Mercedes SUV.
The kidnapped motorist was reportedly told by the brothers that they were responsible for the Boston bombings and the death of a police officer and that if he didn't hand over his car, they would shoot him too.
The driver was held at gunpoint by one of the two men for about half an hour and then released uninjured at a petrol station on Memorial Drive, the road running along the Charles River in Cambridge away from Boston city. One of the brothers later ditched the Honda car and rejoined his brother in the Mercedes SUV.
As police followed the car into the next suburb, Watertown, just west of Cambridge, the two suspects threw three explosives from the car. Three large bangs between midnight and 1am could be heard in the two suburbs. A statement from police, the local district attorney and the MIT police chief said that the suspects reportedly threw explosive devices from the car as police pursued them from Cambridge into Watertown.
Gunfire was exchanged in the Watertown area and one of the suspects, later identified as Tamerlan Tsarnaev (26), the older brother of Dzhokhar Tsarnaev (19), his accomplice, was critically injured. A transit police officer, Richard Donoghue (33), with the Massachusetts Bay Transportation Authority was also seriously injured in the gun fight. Videos recorded by residents of the Watertown area circulated on the internet and on local television stations showed lengthy and heavy gunfire being exchanged outside homes in the area.
Tamerlan Tsarnaev was later identified as “Suspect No 1” by the FBI in a surveillance video of the two suspects on Thursday evening. In the footage of two men walking a few metres apart along Boylston Street, the scene of the bombings, Tamerlan wore a black cap and carried a backpack said to contain the bomb.
After he was critically injured in the Watertown gunfight, his younger brother, described by police as “Suspect No 2” – the man pictured wearing the white cap in the FBI’s images released earlier – was reported by various media to have fled in a car, driving over his wounded brother as he left the scene.
Dozens of heavily armed police officers and FBI agents descended on Watertown and began searching for the remaining suspect in the residential neighbourhood.
As police searched streets house-to-house for the second suspect, the FBI released a new, clearer photo of the two suspects near the scene of the blasts at Monday's marathon in Boston.
Two hours later, at about 4am, Boston Police and Cambridge Police Chief confirmed that the two men involved in the shooting of the MIT police officer, the police chase and shoot-out on the way into Watertown were the same suspects they believed were the perpetrators suspected of planting the Boston Marathon bombs.
The district attorney for Middlesex County, which covers the Boston area, confirmed that "Suspect No 1" had died and "Suspect No 2" had escaped. Tamerlan was admitted to Beth Israel Hospital at 1.20am and pronounced dead at 1.35am. Doctors said he died of gunshot wounds, shrapnel and injuries to the trunk, possibly by his own explosives. They said they treated him without knowing who he was.
Massachusetts state and Boston police spoke publicly for the first time during the night's dramatic events at an outside press conference. They urged residents in Watertown to stay inside and not to answer the door to anyone other than to a uniformed police officer, saying that the suspect at large was believed to be a terrorist and that he was a person "who has come here to kill people".
Reports began emerging that the bomb suspects were from a Russian region near Chechnya, the war-torn region where Islamic insurgents have fought the Russians in separatist wars. The two brothers were reported to have lived in the US for about a decade.
Soon after, Dzhokhar Tsarnaev was named as the Boston bomb suspect who had survived the Watertown gunfight with police hours earlier. Dzhokhar’s older brother, Tamerlan, was identified by a law enforcement official around 8.40am.
The killing of the MIT police officer and the gunfight led to a lock-down of the city.
Massachusetts governor Deval Patrick suspended all public transit services on the Boston area’s T metro system and people living in Watertown, Cambridge and other neighbourhoods were told to stay inside.
The US train network Amtrak closed its rail service between Boston and New York on the well-used Northeast Regional Route.
It emerged yesterday that the two brothers are ethnic Chechens, though they lived in a region near the predominantly Muslim region in southern Russia prior to moving to the US.
The New York Times and CBS reported that Dzhokhar and his parents became naturalized US citizens last year while Tamerlan was reported to be in the middle of the process to become a citizen.
Boston police said that they had searched between 60 per cent and 70 per cent of the houses in a target catchment area in the Watertown area in the hunt for Dzhokhar.
The police said that there was a major crime scene around the Watertown neighbourhood. They called for patience, saying they expected developments over a prolonged period.
The boys’ father, Anzor Tsarnaev told The Associated Press in an interview from the Russian city of Makhachkala yesterday that his 19-year-old son Dzhokhar was a “true angel”, a second-year medical student in the US and “an intelligent boy”.
Their sister Alina Tsarnaev, speaking in New York, was reported to have said she couldn't understand how her brothers were responsible for the Boston bombings and was "shocked" that they had been implicated.
“They were great people. I never would have expected it,” said the woman who was said to be helping investigators. “They are smart – I don’t know what’s gotten into them.”
Speaking to local Boston media in the US, Ruslan Tsarni, an uncle, called on his nephew to turn himself in and “ask for forgiveness” from the victims of Monday’s bombings. He said he had put a shame on his family and ethnic Chechnyans.
He called his nephews “losers” and said any notion that Islam played a part in the attacks is a “fraud”.
As of yesterday afternoon, Boston police continued to search for Dzhokhar in one of the biggest security operations ever seen in the US.