The slaying of 16-year-old Randy Moskowitz continued to baffle Prince George's County police yesterday as a medical examiner reported that the youth was shot six times, at least twice at close range, and that his unemptied wallet was found in his pants pocket.

The youth, an editor of the school newspaper at Northwestern High School in Hyattsville, was found dead Saturday morning in a field across from the Prince George's Plaza shopping mall.

Dr. Hormez Guard, assistant state medical examiner, who perfomed an autopsy Sunday morning, said yesterday Moskowitz was shot from behind and the side, three times in the head, twice in the abdomen and once in the back, possibly with a small handgun.

The fact that Moskowitz's unemptied wallet was found in his pocket perhaps rules out robbery as a motive for the slaying, Guard said.

The car the youth was driving has not been found, according to his parents.

The medical examiner said Moskowitz had bruises on his hands. "He could have been fighting or he could have been trying to defend himself," Guard said. "We don't know yet."

A team of Prince George's County detectives remained "at a complete loss" to explain the slaying.The detectives spent the day interviewing Moskowitz's friends, classmates and neighbors; an extensive search by more than 20 police officers of the area where the body was found uncovered no clues, police reported.

The youth's mother, Isabel Moskowitz, said yesterday her son left the house "to get something to eat" about 5:10 Friday evening.

"The routine was to go and get his pizza [at Mama Lucia's, located at Prince Georgia's Plaza] and go home. He took my car and went to get his food."

The youth never returned.

His parents called county police at 12:45 a.m. Saturday to report him missing.

"He usually called me," Mrs. Moskowitz said. "The time was getting too late. I knew in my heart that something was wrong." Isabel and Nathan Moskowitz heard no word about their son until morning.

"I was sitting in my kitchen when three six-foot detectives walked in with my neighbor," Mrs. Moskowitz said. "They gave it to me straight, there was no hemming of hawing: 'We have found Randy, and he's dead.'"

The Moskowitzes said they have no idea why anyone might want to hurt their only child, by all accounts bright and pleasant to everyone.

"The police won't give us any information," said Isabel Moskowitz, while she and her husband received friends and relatives at their home.

She shook her head. "We are in the dark. We haven't the faintest idea who did it, why . . ."

The family is giving any gifts made in Randy's memory to the high school newspaper, one of the youth's great interests. When her son began working on the "Nor'wester," Mrs. Moskowitz said, he talked his parents into donating an old refrigerator to the newspaper office, and persuaded a neighbor to contribute a spare rug. "He wanted to make it comfortable, pleasant," she said.

Before leaving the house for food on Friday night, Randy Moskowitz had picked up his father, a systems analyst, at a bus stop after work. Though he rarely talked about it with his father, the youth had a strong interest in computer work. His parents said he worked at the University of Maryland facilities during the summer.

During his free time, Randy, diabetic, played Ping-Pong and pinball and went bowling. Because the youth's disease, discovered two years ago, required regular meals and insulin shots, police put out an all-points bulletin for him when the Moskowitzes reported their son missing.

Some students have speculated "that Randy's such a nice kid, he may have stopped to give someone a lift," said Ida Pinkney, an English teacher who knew the youth. "We just don't know why anyone would want to hurt him.

"Sometimes you know youngsters who are always in the middle of things, "but this, the English teacher said, "it's just a senseless, useless killing. It's a waste."