A dragnet was out for a suspect in the point-blank fatal shooting of a policeman in his patrol car moments after he stopped a vehicle.

Youngstown police identified a recently released ex-convict, Martin Louis Koliser Jr., 31, of nearby Austintown, as the suspect in Tuesday morning's killing of patrolman Michael Hartzell, 26.

The suspect served a prison term for felonious assault in a 1996 stabbing and was released in December.

Police said Hartzell stopped a car downtown while investigating a barroom shooting. Koliser was suspected in both crimes.

Hartzell was shot at 2:19 a.m. after he stopped to check a parked Lincoln Town Car that matched the vehicle of a suspect in a shooting at the Casaloma Gardens bar, police said.

While checking the license plate, Hartzell was ambushed, shot twice in the head and once in the bulletproof vest over his chest, Police Chief Robert Bush said.

"The shooter may have exited his vehicle and approached the officer and shot him in the cruiser," Bush said.

Hartzell was investigating the critical wounding of Donel Rowe, 23, of nearby Struthers. His condition was unchanged Wednesday at St. Elizabeth Health Center.

A $10,000 reward for information leading to the capture of Koliser quadrupled Wednesday to $40,000.

Bush said police believe Koliser might be headed to Clearwater, Fla., based on several phone calls he made to people there. He may be driving a 1990 black Oldsmobile Cutlass Calais, a four-door sedan, with a U.S. flag sticker in the rear window.

It was the first death of a Youngstown policeman in the line of duty in 11 years. Hartzell had been with the department since December 2000.

Brian Niceswanger, a spokesman for the Ohio prison system, said Koliser also had served about a month in the Lorain Correctional Institution in 1992 for an escape. He served about 5 years at Mansfield Correctional Institution on the assault charge and was paroled in December.