One suspect in the Boston Marathon bombings is dead. The other — his brother — was on the run Friday, pursued by an army of law enforcement officials whose manhunt virtually shut down the city. A man identified by several sources as Tamerlan Tsarnaev, 26, died after an overnight shootout with police. He’s the man described Thursday by the FBI as black-capped Suspect No. 1 in the attacks Monday that killed three. His brother, Dzhokar Tsarnaev, apparently escaped — leading police to throw a huge dragnet around the region. In photos released by the FBI of the bombing suspects, the younger brother is seen wearing a white cap. The agency called him Suspect No. 2. Violent night The violence began late Thursday with the robbery of a 7-Eleven convenience store, according to Alben. Soon after, in Cambridge, across the Charles River from Boston, Massachusetts Institute of Technology police officer Sean Collier was fatally shot while he sat in his car, the Suffolk County District Attorney’s Office said in a statement. Police believe the bombing suspects were responsible for the shooting. The two suspects, according to authorities, then hijacked a car at gunpoint in Cambridge. They released the driver a half-hour later at a gas station. As police picked up the chase, the car’s occupants threw explosives out the windows and shot at officers, according to the district attorney’s office. Officers fired back, wounding Tamerlan Tsarnaev. He later died at Beth Israel Hospital. A source briefed on the investigation says Tsarnaev was wearing explosives and an explosive trigger when his body was recovered. His brother apparently escaped. Richard H. Donohue Jr., 33, a three-year veteran of the transit system police force, was shot and wounded in the incident and taken to a hospital, a transit police spokesman said Friday. The officer’s condition was not immediately known. Developments moved quickly: — Police, often with guns drawn, continued to chase leads in pursuit of the surviving suspect. In Watertown, reporters were cordoned off and told to stay back. — A Maryland man who said he was the suspects’ uncle told reporters the two men had brought shame on their family and all ethnic Chechens with the attacks, which he called an atrocity. “If you’re alive, turn yourself in and ask for forgiveness,” Ruslan Tsarni urged his nephew. — A former teacher at the high school Dzhokar Tsarnaev attended, who lives near Tsarnaev’s residence now, described the younger brother as “a wonderful kid” who seemed incapable of such violence. — Wednesday, two days after the bombings, Dzhokar Tsarnaev apparently tweeted, “I’m a stress free kind of guy.” Early Tuesday, he tweeted, “There are people that know the truth but stay silent & there are people that speak the truth but we don’t hear them cuz they’re the minority.” — Tamerlan Tsarnaev was wearing explosives and a triggering device when he died, a source briefed on the investigation told CNN’s Deborah Feyerick. – Police ordered businesses in the suburb of Watertown and nearby communities to stay closed and told residents to stay inside and answer the door for no one but authorities. Boston authorities advised the same. The city’s subway, bus, Amtrak train systems and Greyhound and Bolt Bus — a regional carrier — have been shut down. Taxi service across the city also was suspended for time during the manhunt. Every Boston area school is closed. The search followed a violent night in which authorities say the men allegedly hurled explosives at pursuers after killing Massachusetts Institute of Technology police Officer Sean Collier, robbing a convenience store and hijacking a car.