Authorities said a gunman fired into traffic on Memorial Drive before he was shot and arrested.
CAMBRIDGE, MA — Two people suffered life-threatening injuries Monday afternoon when a gunman opened fire on vehicles along Memorial Drive near Harvard University, authorities said, setting off a large police response on one of Cambridge’s busiest roads.
The suspect, identified by officials as 46-year-old Tyler Brown of Boston, was shot by a Massachusetts state trooper and an armed civilian before he was taken into custody. Middlesex County District Attorney Marian Ryan said Brown was hospitalized under arrest and is expected to face charges tied to the shooting.
The gunfire broke out before 1:30 p.m. near Memorial Drive and River Street, close to the Charles River and not far from Harvard Square. Ryan said the gunman had an assault-style rifle and was “actively firing in an erratic fashion at various vehicles.” The two injured people were inside vehicles when they were struck, officials said. One was described as an MBTA van driver, and the other was a man driving on Memorial Drive. Their names were not released Monday night. Officials said both were taken to hospitals with critical injuries. The shooting turned a bright weekday afternoon into a crime scene, with damaged vehicles left on the roadway and police shutting down traffic in the area for hours.
Authorities said Boston police had alerted Cambridge officials before the shooting because Brown was believed to be in the area and may have had a firearm. The warning came shortly before the violence on Memorial Drive, officials said. Brown then began firing at passing vehicles, according to investigators. A state trooper and a civilian described by officials as a former Marine fired at Brown and struck him multiple times. Video from the scene showed a chaotic roadway, with a long gun visible in the area and officers moving in after the suspect was down. Officials did not say how many total shots were fired by Brown, the trooper or the civilian. Some reports said dozens of rounds may have been fired, but the final number remained under investigation.
The location is a major route through Cambridge, running along the Charles River near the River Street Bridge. It sits in a dense part of the city with university buildings, housing, parks and commuter traffic nearby. The shooting happened about a mile and a half from Harvard Square and near routes used by students, workers, cyclists and drivers. Cambridge police said after the shooting that there was no continuing danger to the public. Gov. Maura Healey said there was no ongoing threat and praised the public safety response. The shooting came a little more than a year after a separate gunfire incident at the Harvard Square MBTA station led Harvard University to briefly issue a shelter-in-place alert, though officials have not linked that case to Monday’s attack.
Ryan said Brown is expected to be charged with two counts of armed assault with intent to murder, weapons offenses and other charges. She said he had been under supervision for a prior criminal case. Authorities did not immediately say when he would be arraigned, citing his hospitalization. Investigators from the district attorney’s office, Cambridge police and Massachusetts State Police continued reviewing the scene, witness accounts and video from the area. Officials also were expected to examine the rifle and other evidence recovered near Memorial Drive. The names of the injured victims and the full list of charges had not been released as of Tuesday morning.
Witnesses described sudden gunfire, stopped traffic and people trying to get away from the road. Police cruisers and emergency vehicles blocked Memorial Drive as investigators marked evidence and examined vehicles that had been hit. A black Dodge sedan could be seen off the side of the roadway after an apparent crash. The MBTA said one of its vehicles was involved, and officials said the driver was among those hurt. Ryan said investigators were still working to learn why Brown went to the area and whether anyone had been targeted. Based on the early account from officials, the gunfire appeared to be directed at vehicles moving through the corridor rather than at a specific person.
Memorial Drive reopened Tuesday morning as the investigation continued. Brown remained hospitalized under arrest, and officials had not announced an arraignment time. The next public milestone is expected to be the filing of formal charges or a court appearance once doctors clear him for proceedings.
Author note: Last updated May 12, 2026.