A 16-year-old student at Springarn High School was killed yesterday in what D.C. Police called an accidental shooting when a small caliber pistol the youth and several friends were passing around during a school assembly accidentally went off.

Police identified the victim as Adrian Precia, a tall, thin youth who lived on a quiet, tree-lined street just north of the National Aboretum in Northeast Washington. Known to his friends as Ajax, he was the first student killed at a District public school in a decade.

Tanya Brown, a 17-year-old student who said she was sitting three rows behind Precia and his friends in the cavernous Springarn auditorium when the gun went off, disputed the police account. It "wasn't no accident," she said.

"At first I thought they was playing with the gun," Brown said. "It was small and silver . . . Then their voices started getting louder.

"One dude said he'd shoot Ajax and Ajax say, 'No, you won't.' Then the gun went off and Ajax kind of got up and tried to run away, but his eyes rolled back in his head, and he just fell down and hit his head on the floor."

Charged with homicide in the shooting is Michael Joseph Pratt, 18, of 815 21st St. NE. Also a 17-year-old juvenile who police say owned the unregistered .25-caliber pistol suspected as the death weapon, was charged with possession of a prohibited weapon in the incident.

The shooting occurred during increasing concern among school administrators about security in the high school system where many students routinely carry knives and guns and violent incidents are common. But D.C. School Superintendent Vincent Reed said yesterday the shooting does not "relate to school security at all. It was an isolated incident. A person brought a concealed weapon to school in his pocket. Security couldn't have prevented that."

Mayor Marion Barry said he was "deeply upset by this senseless and unnecessary tragedy -- a young life gone because a way has not been found to prevent our children from carrying guns around."

The 10:30 a.m. shooting threw the school at Benning Road and 26th Street NE into temporary confusion. Students milled about in hallways and in front of the building as school administrators, some with walkie-talkies, tried to get the students to return to class.

According to school and police officials, about 50 students were gathered in the auditorium of the high school for registration. Most were new students, transfers from other schools or dropouts coming back to school, an administrator said.

Inside the auditorium, there were at least four guidance counselors, four teachers and an administrator, who were supervising the students as they went through a processing line, enrolling and scheduling their classes.

In the front row of wooden seats on the right side of the room, Pratt, Precia and several other youths were passing around the pistol, witnesses said. Suddenly, the gun went off.

"It sounded like a firecracker," said one administrator. "We looked around and the guy was on the floor, bleeding and clutching his chest."

Following the shooting, the juvenile accused of owning the gun called his mother and then went with her to police headquarters downtown, holding her hand as they walked into the homicide squadroom where he turned himself in. Pratt was picked up by police at the school a short time after the shooting.

D.C. Deputy Police Chief Alfonze Gibson, commander of the department's criminal investigation division, said yesterday there was "absolutely no evidence of an argument" between the boys. He said he believed, from statements taken by police, that all the youths involved were friends.

Ten years ago, at the time of the last fatal shooting of a student in a District school, acquaintances were also involved.

On Jan. 5, 1970, a 15-year-old Hine Junior High student was shot and killed when a revolver a friend was holding accidentally went off. On that same day, three other unrelated incidents involving guns in schools also occurred.

Since then, periodic shootings and stabbings have continued. Last February, a 9-year-old Langdon Elementary school pupil was shot by a friend.In March, a Cardozo High School student was stabbed in the back after a quarrel. And in April, a 16-year-old student at Lincoln Junior High was shot in the neck during his lunch period.

Straddling a ten-speed bicycle outside Spingarn yesterday and watching television news crews scramble for interviews while school administrators attempted to bring order to the chaos, a youth who identified himself only as "Chico" spoke about guns and the mystique of carrying one.

"It's a fame thing," he said. "You carry a gun in your bag and you cool, man. You walk down the hall and you know that if anybody bump you, you got a gun to do your talking.

"Guns is real big with the craps players," Chico said. "Its that whole underworld trip that people are into. Talking tough, acting tough, being a dude."

And, Chico said, guns are easy to come by. "People drive out to the country and rip off a store or a house . . . then they come back down here and sell you anything you want.

"You can buy a .357 magnum for about $195, a shotgun for $150 or a .38 for $50. But hell, if the gun is hot and the guy wants to get rid of it, you can trade him a radio or a bicycle for it."

Marcus Harrell, another student, said he had known Ajax Precia for about 10 years, growing up in his neighborhood. Ajax was "pretty well known in about a third of the city," he said, "the type that liked to hang out and get in trouble with the police. . . . He was not really much in sports, but he liked to shoot dice."

Ajax dropped out of junior high school about two years ago, Harrell said, and had hung out in the streets. "He didn't have a job. I don't think he ever tried to get one, either."

Friends said yesterday he reenrolled in night school at Springarn earlier this year.

Precia lived with his mother, a government employe, and his father, a construction worker, in a tidy brick home with a vegetable patch out back. A dozen withered stalks of corn swayed there in the summer breeze yesterday.

Another neighbor and longtime friend of Ajax said, "It doesn't shock me to hear that he got killed. The way he lived, it was expected."

The friend who declined to give his name, said Ajax "ran around with thugs." Last Sunday night, he said, Ajax and the juvenile who was charged with possession of the possible murder weapon, had a similar gun with them at the Arboretum Recreation Center.

"They thought they were real cool," he said.

Back at Spingarn, an assistant vice principal said he was "shocked" at the shooting. "Nothing like this ever happened before," he said.