The charred body of a 52-year-old Loudoun County man was found still smoldering outside a Sterling farmhouse near the Northern Virginia Community College campus Sunday night in what police said yesterday they believe to be a homicide.

The Loudoun County sheriff's department said an autopsy report released late yeterday indicated the victim, whose name has not been made public, had been struck on the head with an ax and that threequarters of his body had been burned.

A police spokesman said the man's roommate, 60-year-old Theodore Hardin, had been questioned in connection with the incident, but no arrests have been made. Police said they had several possible suspects in the case.

Lt. Leonard McDonald of the sheriff's office said fire and rescue workers rushed to the rundown farmhouse off Rte. 7 about 7:30 p.m. after receiving a call from Hardin.

They found the unidentified man's disfigured body lying outside the farmhouse with a burned-down cigarette on his stomach and an empty glass nearby. A blood-stained ax was found about 15 feet from the body, officials said.

The autopsy report by the Fairfax County medical examiner's office cited the blow to the victim's head as the cause of death.

The sheriff's department said deputies talked to Hardin late Sunday night and plan to interview him further today.

Hardin said yesterday in an interview he has lived at the farm for two months, caring for 60 pigs and other animals in place of rent. "I'm still trying to figure out how it all happened," he said. "He (the victim) went out in the tractor for three hours and that's the last thing I know."

Sheriff's deputies said the victim, whose daughter lives in the District of Columbia, collected junk and tended the animals on the farm for a living. Although they said they have no motive for the apparent murder, they said they found the victim's pants pockets turned inside out and his partially burned wallet on the other side of the farmhouse from where his body lay.

Deputies said Hardin walked three-quarters of a mile to the nearest house to report the death. The farm house shared by the two men has no telephone.