A man went on a shooting spree yesterday morning in his pregnant girlfriend's apartment, slaying the woman, wounding her 9-year-old son and seriously injuring a 67-year-old neighbor who rushed to her aid, D.C. police said.

Then, brandishing a gun and chanting, "Say no to drugs," the man fled the apartment and shot at a newspaper carrier, police said.

Police arrested Ernest B. Ford, 29, less than two blocks from the apartment building in the 2200 block of Southern Avenue SE. Ford, of 1802 Massachusetts Ave. SE, was charged with first-degree murder while armed and three counts of assault with intent to kill.

Janice Marie Osborne, 28 years old and four months pregnant, was pronounced dead in her third-floor apartment. Her son Michael Johnson Jr. was listed in stable condition last night at Greater Southeast Community Hospital with a gunshot wound..

Listed in serious condition last night was the neighbor, Kenneth Stewart, who police said was shot in the chest and shoulder when he rushed to Osborne's aid after hearing several shots shortly after 8:30 a.m.

The newspaper carrier, Anton L. Brewer, 17, of 1910 Valley Ter. SE, was treated at the hospital's emergency room and released.

Ann James, whose second-floor apartment is directly below Osborne's, said she was in a bedroom watching cartoons with her 3-year-old son when she heard three shots.

James recalled that Osborne had told neighbors that Ford was "displeased" about her pregnancy but that Osborne planned to keep the baby.

Staff writer Douglas Stevenson contributed to this report.