A Youngstown patrolman investigating a bar shooting was shot and killed early Tuesday, and police suspected one man was responsible for both crimes.

The FBI, Ohio Highway Patrol and police from several departments, including K-9 units from Sharon and Sharpsville, searched for Martin Louis Koliser Jr., 31, of nearby Austintown, who had served a prison term for felonious assault in a 1996 stabbing. Police also activated the Emergency Alert System in the eastern Ohio-western Pennsylvania area, saying Koliser was considered armed and dangerous.

Patrolman Michael Hartzell, 26, was shot at about 2:20 a.m. when 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.

The officer was investigating the shooting of Donel Rowe, 23, of nearby Struthers. Rowe, shot in the chest at the bar, was in critical condition at St. Elizabeth Health Center in Youngstown.

The city is offering a $10,000 reward for information leading to the capture of Koliser, wanted on an attempted murder warrant in Rowe's shooting.

Bush said police believe Koliser is possibly heading 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.

"We feel that he will attempt to come up with some money to fund his trip to Florida," Bush said. "We don't know for sure, but we believe he's still in the area."

Flowers, a Teddy bear and several black, star-shaped balloons were placed in front of a vacant shop at the shooting site.

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

"It's an unspeakable tragedy," Mayor George McKelvey said. "We're all experiencing grief for the family of this officer."

Brian Niceswanger, a spokesman for the Ohio Department of Rehabilitation and Correction, 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 placed under supervised parole in December.

The suspected car was parked about 2 miles from the bar, in front of a vacant costume shop in downtown Youngstown.

The shooting happened across an intersection from Powers Auditorium, one of the few places that attracts large crowds in a downtown that has few restaurants or night spots.

There was a sold-out performance at the auditorium Monday night of a Broadway production of "Saturday Night Fever."

"At 2:30 in the morning downtown is an extremely quiet place," the mayor said. "Crime is literally nonexistent in the area."

Marty Berendt, who runs an electronics store on the street, said there usually are not any problems in that part of downtown.

"Most of the time it's quiet," Berendt said.

Hartzell, who was to be married in August, leaves a fiancee, his parents and a brother.

His mother, Mary Kay, is the treasurer at Austintown Fitch High School, which Hartzell attended.

"It's just one of those unbelievable days that you don't think can happen," Principal Doug McGlynn said.

McGlynn described Hartzell as quiet, responsible and a good student.

"He was a great kid, and he always wanted to give to others. He always wanted to do public service. He fulfilled his dream. Unfortunately, it was a short dream."

Also assisting in the investigation were the Bureau of Alcohol, Tobacco and Firearms, sheriff's departments and police departments in West Virginia.

Herald staff contributed to this report.