D.C. police said yesterday that they have no suspects and no leads in the Thursday night slaying of Mary Lazarou, a 22-year-old Washington Post editorial aide who was found shot to death in her Northwest Washington apartment.

Meanwhile, the Washington Post Company announced that it would offer a $5,000 reward for information leading to the arrest and conviction of the person or persons responsible for Lazarou's death.

The anouncement was made in a letter to Police Chief Maurice Turner from Thomas Ferguson, Post president and general manager.

Detectives said there were no indications of a forced entry into the apartment or of robbery, and that they found no signs of a struggle.

"We're hoping the reward money will generate some additional information," said Lt. William Ritchie, a spokesman for the homicide branch. Persons with information are asked to telephone 727-4347.

Four coworkers who were planning a housewarming party for Lazarou found her lying unconscious near the unlocked door of her efficiency apartment on the fourth floor of the Latrobe apartment building at 1325 15th St. NW. She had been shot once in the head.

Lazarou had moved into the apartment only Wednesday, and apparently went there from work sometime before 5 p.m. Thursday. Her coworkers arrived around 6:30 p.m. and were admitted to the Latrobe by a building employe when Lazarou failed to respond to a call from the downstairs vestibule.

One detective said the shooting might have occurred after the assailant had been in the apartment for some time, but that it was also possible the victim had been shot as she answered a knock at the door.