The body of a 22-year-old man was found shot to death in an Olney town house yesterday, and his death brought to 22 the number of people slain in Montgomery County this year, matching last year's record number of homicides.

Joseph B. Nolan was found about 9 a.m. lying nude in the living room of a two-story town house in the 3200 block of Spartan Road, in the Camelback Village development, Sgt. Harry Geehreng said. Police have made no arrests in the slaying.

Nolan, a repairman for Anthony Pools in Rockville, had been shot once in the chest, Geehreng said. Police retrieved a .22-caliber rifle believed to have been used in the shooting from behind shrubbery near the front door, he said.

Geehreng said Nolan's roommate, Demetrius Katrivanos, called police about 8:20 a.m. yesterday to ask authorities to check on Nolan. Katrivanos, who said he had spent the night at his parents' Rockville home, told police he was concerned because of a death threat left on his answering machine, Geehreng said.

According to police, Katrivanos, 20, said the threatening message stated, "I've already got your roommate, you are next."

Yesterday, neighbors in the condominium community off Route 108 said the two men had hosted a Halloween party Wednesday night at the town house. Two beer kegs and several bags of trash were still on a balcony outside the living room where Nolan's body was found.

Geehreng said police believe Nolan was killed Wednesday night. Police found a small amount of marijuana and beer containers in the house, he said.

So far this year, Montgomery County police have investigated 20 homicides. Takoma Park police handled a double slaying linked to an alleged embezzlement scheme by a Navy disbursing clerk.

Most of the homicides this year have involved domestic disputes or robberies, according to police records. Police linked drugs to the April slaying of a man whose body was dumped on a Silver Spring street. Also this year, a Bethesda jeweler was charged with fatally wounding two men after an alleged robbery attempt, and a college student was slain after being approached by three men posing as postal carriers.