D.C. police said yesterday they do not have a motive in the execution-style slayings of four persons in a Southeast Washington apartment, and that they will look closely at the backgrounds of the victims for clues.

Police sources said that as many as 11 shots may have been fired from one or possibly two small caliber weapons in the deaths of Carolyn Resper, 26, Juanita E. Beasley, 22, Reginald Harris, about 27, and Ronald Best, mid 20s.

The bodies were discovered Tuesday in an apartment Resper and Beasley shared at 2839 Robinson Pl. SE, after Resper failed to appear in D.C. Superior Court to testify against her estranged husband in a robbery case and detectives were sent to find her.

Beasley and Harris, of 1314 S. Walter Reed Rd., Arlington, died of multiple gunshot wounds in the head, officials in the D.C. medical examiner's office said yesterday. Best, of 2842 Robinson Pl. SE, died of multiple gunshot wounds in the head and neck, and Resper died of multiple gunshot wounds in the head and arm, officials said.

An official said ballistic tests will be conducted to determine if more than one gun was used in the slayings, the largest multiple homicide in the city in more than 12 years.

Police believe that the victims had been dead about eight hours when their bodies were found, putting the time of the shootings at about 2 a.m. Tuesday.

Although some residents in the neighborhood reported hearing a "disturbance," according to police, sources in the police department said they were baffled that apparently no one heard any shots.

"We were up all Monday night till 6:30 or 7 a.m. Tuesday morning, and we didn't hear a thing, not a thing," said Barbara Waters, who lives one floor above the apartment where the bodies were found.

Carolyn Resper's sister, Delores Holmes Mays, said yesterday she had talked with two of her sister's friends who said they had called Resper at the apartment about 11 p.m. Monday and that nothing appeared to be wrong.

Mays said that "a few months ago" Resper told her that she had been "threatened" about testifying as a prosecution witness in a 1982 armed robbery case against her husband, Ronald Resper, and his brother, Wayne.

Carolyn Resper had testified against them before the grand jury that indicted them on armed robbery, burglary and other charges stemming from a holdup at the ANA Towing Co., 519 K St. NW, on Dec. 5, 1982, according to court papers. The trial was scheduled to start Tuesday.

Mays, who said that she also was scheduled to testify against the brothers, said she was present when her sister told Assistant U.S. Attorney Robert Reed about threats made against her relating to her testimony.

Reed could not be reached for comment yesterday.

According to Ronald Resper's attorney, Henry Schoenfeld, Reed stated Monday that Carolyn Resper had told him that her husband had threatened to keep their three children away from her unless she decided not to testify in the case. Schoenfeld said that Ronald Resper denied making any threats.