The body of a 34-year-old D.C. Superior Court probation officer who apparently had been strangled was found yesterday in his apartment in Washington, police reported.

The victim was identified as Billy T. Jennings, of 1435 Fourth St. SW, an eight-story apartment building whose recent tenants have included at least one congressman and an assistant secretary of state.

According to accounts of neighbors and police, a friend found Jennings' body about 2 p.m. yesterday in the bathroom of his fifth-floor apartment.

Police said they believed Jennings had been dead for a day or more.

According to investigators, there was no sign of forced entry at the victim's apartment, but they said one or more items apparently had been taken. They said they had determined no motive for the slaying

Jennings, who worked as a diagnostic probation officer, wrote presentencing reports on offenders who had been convicted or had pleaded guilty in Superior Court.

One neighbor in the apartment building, known as Finley House, described him as a "hell of a nice guy," a sentiment echoed by one of Jennings' supervisors at the court.

"He was very well liked," the official said last night. 'He did very good work."

Jennings had gone to Europe on vacation in December, and was to have returned to work on Wednesday. He did not report, but instead called in sick, a supervisor said.

Neighbors said a friend who became concerned when he had not heard from Jennings for some time went to the apartment yesterday afternoon and discovered the body.

Supervisors at Superior Court said they knew of no threats received by the victim in the course of his work.

One person familiar with the apartment house said the victim's apartment was ransacked last summer during a break-in.

Among the current tenants at Finley House is Alfred Atherton Jr., the U.S. ambassador-at-large who has been involved in the recent Middle East peace negotiations.

An autopsy is scheduled today to make a formal finding of the cause of Jennings' death.