A Wheaton High School assistant principal, charged with attempted murder Friday night for allegedly shooting a handgun into a crowd of students, said yesterday that he actually was firing into the air to chase away six or seven men who had been in his backyard and had fired a gun at him.

Sandy N. McDonald, 53, who acknowledged that he has been the target of student harassment and vandalism for at least the last five years, said he did not intend to shoot toward the students, who were milling around cars parked a block from the school near where McDonald lives.

One student, Matthew Jones of Rockville, was treated for a minor injury after a bullet grazed his arm.

McDonald and several students who witnessed at least part of the incident have given conflicting accounts of what happened.

"I was not shooting to hurt or kill anyone," McDonald said. "I wanted to shoot to frighten people away from the house, to frighten them away from my wife and children. I wad frightened and I was angry."

Montgomery County police said the McDonald Family, which is black, has been harassed repeatedly and their property damaged by vandals more than a dozen times in the last five years. The police said at least some of the harassment has been racially motivated in the largely white, middle-income neighborhood.

McDonald said he had been called home about 9 p.m. from a nearby friend's house by his wife, who said their two daughters had been verbally abused while walking home from a school pep rally that had just ended. Students who were interviewed said someone among them did made racial remarks to the two daughters.

Arriving home, McDonald said he saw a small group of men, all of them white, about 24 or 25 years old and wearing blue jeans and jackets, standing in his backyard. "I didn't recognize them," he said. "They weren't students."

McDonald said he got his .22-caliber handgun and walked into the backyard. "One [of the men] fired a gun at me," said McDonald. "I fired one shot in the air," he said, and the men ran. McDonald, who said the group of men had at least two guns, said he pursued the men, firing three shots into the air as he ran after some of the men who had run toward the students.

Three students interviewed yesterday said they did not see the men McDonald said he was chasing, nor any men with guns. "The only people on the street were kids from school," said Robbie Cross, a senior at Wheaton who said he was standing with five other students at the intersection of Farthing and Fredale when McDonald came running toward them, firing his gun.

"I saw sparks coming out of the barrel," Cross said. "He was saying, "I'm going to get you. I'm not going to take it no more.'"

Just before the shooting began, student Tom Carney, who was in the crowd, said McDonald had passed by the students in his car, driving wildly. "We started yelling at him because he was driving crazy," Carney said. The students said McDonald drove to his home, just missing three parked cars, rushed inside his house and emerged moments later with his gun.