A shooting on Memorial Drive in Cambridge, Massachusetts, left two men with life-threatening injuries after a gunman opened fire with an assault-style rifle on Monday afternoon.

The suspect, 46-year-old Tyler Brown, was shot by both a State Police trooper and a civilian after allegedly firing dozens of rounds at passing vehicles and causing widespread panic.

Authorities said Brown had previously made a suicidal statement and was the subject of a police welfare check shortly before the attack began.

Investigators reported that at least a dozen vehicles were struck, including a postal truck, and described the scene as an active shooter situation that lasted only minutes due to the rapid response, CBS News has reported.

Brown, who has a prior conviction for firing at a Boston police officer, is in custody and facing multiple charges including armed assault with intent to murder.