A 28-year-old railroad porter, apparently under the influence of the hallucinogenic drug PCP, slashed his mother with a broken Coke bottle and threatened to kill her early yesterday, before a D.C. police officer shot and killed him in an alley outside the family's Northeast Washington home.

Frank Quarterman died at Washington Hospital Center at 7:05 a.m. less than an hour after Officer Wilson F. Pumphrey, a 16-year police veteran, fired a single shot at Quarterman, who was forcibly holding his mother behind the family home at 3927 South Dakota Ave. NE.

The slain man's father, Alan Quarterman, returned home from a fishing trip two hours after the shooting and found his son dead and his wife hospitalized with cuts on her back and chest.

"It was not his decision to make," the father said of the policeman, with tears streaming from his eyes as he slumped alongside a porch railing. "It was not necessary for the police to shoot him, but they shot him like a dog, in his mother's arms."

Lavonia Reed tried to comfort her father. "Listen, Dad," she said. "Frank was going to kill Mama. If the officer had not fired, he (Frank) would have cut her throat, like he said he would. The only reason Mama is alive, Daddy, is because the officer reacted in time."

Pumphrey, described by colleagues as "visibly shaken" by the incident was placed on routine administrative leave pending the results of a grand jury investigation, the standard procedure in all fatal shootings involving police.

Dolores Quarterman, the mother, was reported in stable condition at the hospital yesterday.

Lt. Kenneth Winters of the homicide division said that Frank Quarterman, a porter with Amtrak, had either been drunk or on drugs at the time of the incident.

"He was tearing up the basement and the mother went downstairs," Winter said. "He took her out of the house and apparently drove the family car somewhere up on Eastern Avenue." Winter said that Frank Quarterman abandoned the car and walked his mother back home, allegedly making threats and slashing her as they went along."

Lavonia Reed recalled that when Frank and his mother arrived back home, the mother was in "pretty bad shape. "I yelled 'here they come,' and the policeman showed up at that time, Reed said.

According to family members, both Frank and his mother appeared to be holding on to one another.

"I told Frank to put the Coke bottle down," said Zontine Reed, Lavonia's husband. "He began staggering backwards and asked for the car keys. I told him no and he was just standing there."

Lavonia Reed said she had talked to her brother about two weeks ago about his occasionally smoking PCP, which is also known as angel dust. "He didn't smoke it every day, but he has been smoking for about two or three years."

PCP, developed as an animal tranquilizer, has mind-expanding qualities similar to LSD, another hallucinogen, and has replaced LSD among many users of illegal drugs. It has been associated with drastic personality changes in habitual users.

On Saturday morning, when Frank Quarterman began tearing up the basement, he had apparently been smoking the drug, according to family members. Shortly after the incident, the basement room was still in disarray with curtains ripped from the windows and glass smashed out. One front basement window had one curtain, still on the rod, protruding from it.

Police said that when the office confronted Quarterman behind the house, he was still holding his mother. "Because of the mother, the officer kept his distance," Winters said. Quarterman repeatedly threatened to kill her and slashed her several times, according to Winters.

"At some point, she fell, and the officer (fired). He was still holding the glass in his hands and making threats to the officer," Winters said.

"It's a very trying situation for the family," Winters said. "The brother's dead, but they didn't want anything to happen to the mama."

On Friday, Frank Quarterman had appeared in D.C. Superior Court on a charge that he put $18 worth of gasoline in his car and drove off without paying. The station owner was a former employer. The case was continued until Monday.

According to Zontine Reed, who had driven around with Frank on Friday, Quarterman was upset about his recent separation from his wife and five children.

Quarterman had moved back in with his parents about four months ago. Zontine said that Quarterman was also having trouble on his job, and did not expect to have it much longer.