CAMBRIDGE, MASSACHUSETTS — A gunman opened fire with an assault-style rifle on passing vehicles along Memorial Drive in Cambridge, Massachusetts, on Monday afternoon, wounding two men before being shot and taken into custody. The suspect was identified as 46-year-old Tyler Brown of Dorchester, who fired between 50 and 60 rounds and struck at least a dozen vehicles, according to investigators.

Cambridge Police responded to reports of gunshots on Memorial Drive near River Street at about 1:30 p.m., between River Street and Pleasant Street Extension. Videos from the scene showed the gunman walking down the middle of the roadway, firing and waving a rifle. "It was already an active shooter situation," Middlesex District Attorney Marian Ryan said.

At about 12:30 p.m., police had attempted a well-being check at Brown's home in Dorchester after his parole officer reported he had made a suicidal statement. A photo of Brown was included in an officer safety bulletin issued Monday morning. Shortly after 1 p.m., Cambridge Police received a 911 call from Boston Police reporting that Brown was in the area with a rifle.

Two men in separate vehicles were shot and are being treated at Boston hospitals for life-threatening injuries. A U.S. Postal Service truck was struck by gunfire, with a bullet penetrating its windshield and hitting near the driver's headrest. A Massachusetts State Police cruiser was also struck.

A Massachusetts State Police trooper and a civilian former Marine with a license to carry a firearm approached the gunman as bystanders fled. Both fired their weapons, striking Brown multiple times in the extremities. State Police troopers provided first aid to Brown and the two wounded men before they were transported to hospitals. Emergency medical services treated at least one individual for a gunshot wound at the scene.

Brown is being treated for gunshot wounds in the intensive care unit at a Boston hospital. He faces charges including two counts of armed assault with intent to murder. Investigators do not believe Brown knew any of the people in the vehicles he struck. In 2021, Brown was sentenced to five to six years in state prison followed by probation for firing at a Boston Police officer in the South End.

"There is no ongoing threat to the public. However, residents and commuters are strongly encouraged to avoid the area to allow public safety personnel to do their work." Governor Maura Healey said.

The River Street Bridge between Cambridge and Boston was closed to all traffic during the investigation. Traffic on Memorial Drive was closed and reopened late Monday night. State Police asked anyone with video of the shooting to contact them, and said hundreds of witnesses will be interviewed in the coming days.