A 19-year-old District man pleaded guilty yesterday to first-degree murder in the Aug. 15 slaying of Ray Heidebrecht, 39, a Marine Corps civilian computer specialist who was stabbed to death in his Alexandria home.

Police believe that Daniel W. Warfield Jr. committed the murder because Heidebrecht was trying to break off their relationship, although Warfield gave police a different account, Deputy Commonwealth's Attorney Krista Boucher said during the hearing at Alexandria Circuit Court. Boucher told the judge that the two men had argued about whether Heidebrecht would continue to support Warfield financially.

Warfield faces 20 years to life in prison when he is sentenced Feb. 24. Boucher said that Warfield had "absconded" from Riverside--a D.C. facility for troubled youths where he had been living--before the killing.

Scott Fidler, a neighbor of Heidebrecht's, found his body Aug. 16 with a butcher knife in his neck, Boucher said. Heidebrecht's car was missing, as were other of his possessions.

Three days later, Alexandria detectives recovered the victim's car from the District, and Warfield's fingerprints were found on some of the stolen property, Boucher said.

Warfield did not comment on the details of the slaying at yesterday's hearing. Public Defender Melinda Douglas, whose office represented him, also declined to comment.

According to Boucher, Warfield admitted to police that he had killed Heidebrecht. He said he had met Heidebrecht only 10 days before and had just asked for a place to sleep.

He told police that he had gone to bed on the morning of Aug. 15 on the floor next to Heidebrecht's bed and that Heidebrecht made three sexual advances toward him, Boucher said. Warfield said he then retrieved a knife from the kitchen and stabbed Heidebrecht, according to the prosecutor.

"He said he had taken all the victim's property as an afterthought since he was homeless," Boucher said.