A 29-year-old Canton man is being held without bail after prosecutors charged him with murder in the shooting death of a Cambridge city worker on the Fourth of July.

Xavier Bautista, 32, a Cambridge Department of Public Works employee, left his home around 4 a.m. on July 4 wearing his work clothes. Investigators say multiple masked men confronted and shot him near Norfolk Street and Broadway in Cambridge. Passersby found him lying between a parked car and the curb around 5:24 a.m. and called police; he was pronounced dead at the scene from two gunshot wounds.

Rayquon Brown was arraigned Monday on charges of murder, carrying a firearm without a license, conspiracy to commit murder, and a firearm enhancement tied to prior convictions, Middlesex District Attorney Marian Ryan said. Prosecutors allege Brown served as a lookout during the attack. "During the shooting the defendant allegedly acted as a lookout and potential backup holding an object which appears consistent with a firearm, at one point holding it outstretched as if aiming it," Ryan said.

Ryan said witness interviews and video evidence led investigators to Brown and his vehicle at the scene. Prosecutors allege Brown and the other men involved fled in a white Dodge Ram pickup truck. The other men have not been publicly identified.

Investigators say there's no known connection between Brown and Bautista, and the motive remains under investigation.

The killing has reignited debate in Cambridge over the city's decision earlier this year to deactivate its ShotSpotter gunshot detection system. Cambridge police say they've increased patrols in the area since the shooting.

Brown's next court date hasn't been publicly scheduled. Anyone with information can contact the Middlesex District Attorney's office or Cambridge Police.