District of Columbia police warned the public yesterday to look out for a man they suspect has been involved in at least 15 rapes in a small area of Anacostia this year.

Police said the suspect accosts women heading for or waiting at bus stops in the early morning, robs them at gunpoint, then forces them into nearby abandoned buildings or wooded areas and rapes them.

The suspect, who usually wears a bandanna drawn around his face, was described by police yesterday as a slender but muscular black man, between 20 and 30 years old, about 5 feet 7 inches tall.

He is suspected of rapes in an area that includes the 2700 through 2900 blocks of Martin Luther King Avenue SE; the Barry Farms public housing development; the 2600 block of Pomeroy Road, and the 600 block of Alabama Avenue SE.

Several victims have told police that the man was armed with a small handgun, and either told them that he was from Baltimore or that he needed money to return to Baltimore, police said.

"We want the public to be alert," said sex squad Lt. Eric Mines. He suggested that women in that area be especially careful in the early-morning hours when waiting at bus stops, and advised them to travel to and from work in groups and to check bus schedules so they will not have to wait for more than a few minutes.

Mines said police went back through the records of several rapes and discovered a pattern that seemed to link at least 15 that took place between Jan. 1 and Aug. 17. The common characteristics included the time of the rapes, general location, description of the suspect and proximity of the victims to a Metro bus stop.