A motorist opened fire on a group of Hell's Angels motorcyclists along Interstate 95, killing one and injuring another, police said.

The bikers were traveling near West Haven around 3:30 p.m. Sunday when they were shot, said State Police spokesman Sgt. J. Paul Vance.

Police were considering a number of possible motives including road rage, and authorities across the Northeast were alerted to look for a green GMC sport-utility vehicle with Florida plates, Vance said. He said police believe four men were in the vehicle.

One of the bikers, Roger Mariani, 61, of Stratford, pulled over before realizing he had been shot in the upper torso, Vance said. He later died at the Yale-New Haven Hospital.

The injured biker, Paul Carrol, 37, of Bridgeport, was grazed by a bullet, treated at the hospital and released, Vance said.

Members of the motorcycle club gathered at Yale-New Haven Hospital Sunday night, prompting police to station officers there to keep order, though police spokeswoman Bonnie Winchester said there were no incidents at the hospital.

The investigation snarled highway traffic for hours, bringing cars to a standstill on Interstate 95. Vance urged anyone who witnessed the shooting or anything suspicious in the area to call police.