Dennis Dolinger, an advisory neighborhood commissioner and a veteran community activist who had worked to curb crime in his area, was found slain yesterday inside his row house on the eastern edge of Capitol Hill.

Police said Dolinger, believed to be in his early fifties, was found about 5 p.m. at 1516 Potomac Ave. SE after police received a call telling them that a man had been shot in the head. Investigators remained at the house, near the Potomac Avenue Metro station, late into the night. However, no cause of death was released, and sources said he may have been beaten.

Neighbors said Dolinger had occasionally been harassed, but police gave no motive in the killing and said they had made no arrests.

"It's a wide-open case," a police spokesman said.

Neighbors, other Advisory Neighborhood Commission members and D.C. Council member Sharon Ambrose (D-Ward 6) said Dolinger had retired or gone on leave recently from the Metro transit system, where he had been a budget analyst.

Neighbors said he had attended a community anti-crime meeting Thursday night at the 1st District police substation on Capitol Hill.

"It's a real loss of a hard-core community worker who was really about building a strong community policing effort in this neighborhood," Ambrose said.

"This is a huge loss," said a neighbor, Jack Calhoun. "He was one of the most committed neighbors we ever had."

Police gave no indication of any motive. A neighbor, Jim Meyers, said Dolinger had had been robbed several times while living at a previous address, also on the eastern edge of Capitol Hill.

Police said there was no sign of forced entry at his current house, a two-story structure with a front porch roof held up by square brick columns.

According to those who knew him, Dolinger had headed the Orange Hat Patrol, a citizen anti-crime unit, in his neighborhood, worked closely with the police department and was prominent in efforts to deal with abandoned and untended houses and lots.

"Community work was his love," said Beth Purcell, who worked on neighborhood projects with him. "If you needed to get something done, he was on the short list."

Ambrose said Dolinger had lived in the neighborhood for about 20 years and moved to the Potomac Avenue address two or three years ago.

"He was well-known," said Meyers, "one of the most visible leaders in the campaign against drugs and guns" in his section of Capitol Hill. "He was at all the meetings."

Ambrose said that Dolinger's efforts to dislodge drug dealers from the neighborhood inevitably created some friction. "It's true of a lot of people who live in communities really troubled by active drug dealing," she said.

A neighbor said Dolinger had recently told her about being harassed while working to improve a nearby park. Ambrose said that Dolinger was an ANC member who represented one of the single-member districts in ANC 6B, one of the three commissions within Ward 6. ANCs were created by law to advise the city's administrative bodies and take positions on such matters as zoning and alcoholic beverage licenses.

Dolinger was first elected to the ANC in 1992.

Staff writers Maria Elena Fernandez and Allan Lengel contributed to this report.

CAPTION: Homicide detectives investigate a fatal shooting on Capitol Hill. Police identified the dead man as Dennis Dolinger, a community activist.