Alton F. Brown Jr., a 21-year-old Northwest Washington man walking to a store near his home to pick up an order of chicken, was shot to death yesterday by a man in his late 60s who then committed suicide.

The incident occurred a few minutes before 2 p.m., at 14th and Randolph streets NW, without any word being spoken or warning given, according to witnesses. The assailant fired a shot into Brown's face from a few feet away with a .38-caliber pistol.

Then, as stunned and terrified onlookers stared, the man seemed to spin and stagger about for a moment. He then fired one shot into the air and a final shot into his own head.

Brown, a landscaper, who lived in an apartment at 3802 14th St. NW, was pronounced dead at the scene.

His assailant was taken to the Medstar Unit at Washington Hospital Center, where he was reported dead on arrival.

Police declined to give his name until relatives are notified.

The incident appeared to be a random and inexplicable event.

Although the two men probably were known or recognizable to each other as fellow residents of the upper 14th Street neighborhood, there was no oral exchange between the two in the moments just before the shooting, according to one D.C. police homicide investigator.

"No contact, no robbery, no argument," the detective said. "There does not appear to be any reason for the shooting."

Investigators and neighbors said that while the assailant gave no indication of presenting any danger to himself or others, he behaved erratically at times.

According to various accounts, the assailant drank heavily and spent much of his time in a parking lot at 14th and Randolph, drinking, muttering to himself and taking what one detective described as an "overprotective" interest in his apartment house, shooing children from the vicinity.

Although he "seemed pretty strange," the detective said, he also "seemed harmless."

Brown, according to authorities, lived with his father. Residents of the area said that just before the shooting, he had been talking with friends about a block from the Randolph Street intersection.

After a while, he told them that he had called the store at the intersection and ordered chicken. He said he was going to walk over to pick it up. He told them to wait for him and walked off.

D.C. police reported three other unrelated homicides Thursday night and yesterday morning.

About 8:30 p.m. Thursday, they said Mervin E. Archer, 28, of 1830 Stanton Terr. SE, was shot fatally outside his home. No one has been arrested.

About 10:10 p.m., they said James Brayboy, 51, of 642 11th St. SE, was shot and killed in an argument at 1511 Isherwood St. NE. Detectives said William Harrell, 42, of the Isherwood Street address was arrested and charged with homicide.

In the third incident, an unidentified 24-year-old man, described as of Latin-American origin, was stabbed fatally about 4 a.m. yesterday in the 200 block of Fourth Street SE. Police said they arrested Jose Garcia, 26, of 3132 16th St. NW, and charged him with homicide.

In the fourth incident, a Southeast Washington man was shot to death last night following a domestic quarrel at his home.

Police said Kevin Gilmore, 24, of 1601 17th St., was pronounced dead at the scene. The victim was believed to be in his early 20s.

Police said Lawrence Eugene Smith, 35, of the same address has been charged with homicide. They said Smith is a cousin of the victim.