A self-professed male prostitute, charged last month in Alexandria in the murder of a funeral home director there five years ago, has been charged in the District of Columbia with an unrelated 1974 murder.

D.C. police said the suspect, Charles William Zeider, 26, of Richmond, was charged last week in a D.C. Superior Court murder warrant with the Jan. 15, 1974, slaying of Robert King.

King was beaten to death during a fight at a motel on New York Avenue NE, D.C. police said.

Zeider was charged Sept. 11 by Alexandria police with murder in the shooting death of mortician Joseph J. A. Jessell Jr., whose body, clad only in a shirt and tie, was found in a gutter on March 3, 1974.

Although Zeider's arrest by Alexandria police was facilitated by information gathered in a D.C. police investigation of several unsolved 1974 homosexual murders, officials said the two charges are unrelated.

Despite the objections of Alexandria prosecutors, who disclosed the District charge against Zeider at a bond hearing in the Jessell case yesterday, General District Judge Robert Colby agreed to reduce Zeider's bond from $100,000 to $50,000.

Zeider remained in the Alexandria jail yesterday, despite the reduced bond.

Alexandria police have also obtained a murder warrant against Scott Watson, 24, in connection with Jessell's death. He was still being sought today.

It could not be learned whether District police were seeking other suspects in King's death.