The Hunt for the Boston Bombing Suspects

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The scene near the M.I.T. campus.

Campus police officer shot

Stata Center, M.I.T. – One day earlier, about 10:30 p.m. on April 18, two men approach a campus police officer from behind and shoot him to death. The officer is found with multiple gunshot wounds and is taken to Massachusetts General Hospital in Boston, where he is pronounced dead. Police believe the officer was killed after a failed attempt by the suspects to steal his gun.

Armed carjacking

Allston – A short time later, a man who officials believe was Tamerlan Tsarnaev approaches a parked Mercedes-Benz S.U.V., climbs in and points a gun at the driver, stating, "Did you hear about the Boston explosion?" and "I did that," according to a criminal complaint filed April 22. The gunman forces the victim to drive to another location, where they pick up another man, who officials believe was Dzhokhar Tsarnaev.

The suspect is caught in a security video at Shell gas station.

Carjacking victim escapes

Cambridge – The two men and the victim drive to a Shell gas station on Memorial Drive in Cambridge. The two men get out of the car, and the victim manages to escape.

Car chase, explosives thrown

Watertown – The police immediately begin to search for the Mercedes, pursuing it into Watertown. During the chase, explosives are thrown from the vehicle.

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Police investigate along Dexter Avenue.

Shootout and killing of one suspect

Watertown – Suspects and the police exchange gunfire. A Watertown resident, Andrew Kitzenberg, 29, said he saw two men engaged in “constant gunfire” with police officers. A police S.U.V. “drove towards the shooters,” he said, and was shot at until it was severely damaged. Mr. Kitzenberg said he saw the shooters throw a bomb at the police, but it “went 20 yards at most.” One of the suspects, Tamerlan Tsarnaev, is tackled by the police and critically injured. He is pronounced dead at a hospital at 1:35 a.m. His brother, Dzhokhar A. Tsarnaev, gets back into the S.U.V. and drives at the officers, breaking through them.

Manhunt continues for second suspect

Watertown – The police begin a door to door search for Dzhokhar Tsarnaev. At a press conference about 12:30 p.m., Massachusetts State Police says that they have completed over “60 to 70 percent of what we want to cover.”

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Suspect taken into custody

Watertown – Friday evening, Dzhokhar Tsarnaev was taken into custody after a standoff with authorities in a residential area. Following a day of door-to-door searches, officers had swooped down on a residential block, focusing their attention on the backyard of a home there. Several blasts were heard around 7:50 p.m.