A 19-year-old Northwest Washington man was charged yesterday in the stabbing of Ray Heidebrecht, 39, a Marine Corps civilian computer specialist who was found slain in his Alexandria home Monday.

Alexandria detectives learned yesterday that Daniel W. Warfield, the man they were looking for in the city's second homicide this year, was already being held on $2,500 bond at the Charles County Detention Center in La Plata, police said. They said Warfield, of the 1300 block of Belmont Street NW, had been arrested in Charles County on unrelated charges Friday, about the same time they were obtaining a first-degree murder warrant for him.

Police said they got a break in the case Thursday night, when Heidebrecht's missing maroon 1999 Isuzu Rodeo was found in the District. Officers watched the vehicle in the 1800 block of Ingleside Terrace NW for about five hours, then impounded it about 9 p.m. to search for evidence.

"Through recovery of the victim's vehicle and following up other investigative leads, police were able to identify Warfield," police spokeswoman Amy Bertsch said. "Police are still investigating the relationship, if any, between the victim and the suspect."

Alexandria police had been looking in the Washington gay community for clues in the weekend slaying, leafleting bars in the Dupont Circle and Southeast Washington areas, where Heidebrecht was known to have been a patron.

A neighbor, Scott Fidler, had discovered Heidebrecht's body early Monday, when he went to check on him at his home in the 300 block of LaVerne Avenue.

Heidebrecht was diabetic, and as a safeguard, he used his porch light as a means of communication with neighbors. Fidler became concerned because he had last seen his neighbor on the afternoon of Aug. 14. There was no sign of Heidebrecht's car, and the porch light had not been turned on as expected.

An autopsy confirmed that Heidebrecht died of a single stab wound.

Heidebrecht's death struck the close-knit Mount Jefferson community especially hard. He was always there to help, whether it was under the hood of a car or with a teenager's homework, neighbors said.

At Henderson Hall in Arlington, where Heidebrecht was the information systems management officer, colleagues described him as one of the most conscientious, hard-working people in the battalion.