Why a 12-year-old boy brought a semi-automatic handgun to school Friday, where he got the weapon, and why he shot at the vice principal are questions deputies were trying to answer after a shooting at a Salt Lake County school.

Deputies were checking stories that the boy had made a threat toward a teacher, "but the substance of that threat is not known at this time," said deputy Steve Thomas.A check of the .22-caliber handgun's serial number showed the weapon has not been reported stolen, but officers were still unsure how the student obtained the weapon.

The shooting incident at Thomas Jefferson Junior High School, 5850 S. 56th West, started about 9:15 a.m. when a teacher alerted Vice Principal William Crumbaugh after noticing a boy had a folding knife and several .22-caliber rounds, Thomas said.

"Mr. Crumbaugh went to the classroom and pulled him out of class and was in the process of bringing him to the administrative offices when he bolted out the door," Thomas said. After the vice principal pursued the boy outside, he said, "the boy stopped in the parking lot, turned, leveled a pistol toward Mr. Crumbaugh and fired."

No one was injured, but a slug hit the outside wall of the gymnasium on the school's west side. Thomas said he did not know how many shots were fired.

The boy continued his flight from the school but was apprehended several blocks away and taken into custody.

The boy told deputies where he got the gun, then changed his story later, Thomas said. "We're looking at the possibility the gun was stolen."

The school building was locked down after the shooting to keep anyone from entering or leaving the building.

School spokesman Chris Stoker said all of the students were in classrooms taking aptitude tests at the time of the incident.

Granite School District spokesman Loren Burton said he had not heard about the boy's motives, but hoped the shooting was an isolated incident.

Salt Lake County Sheriff Pete Hayward said officers assigned to each high school in the unincorporated county and their feeder schools confiscate weapons from students almost daily (see related story on B1). Most of the time, the weapons are taken to show off to other students.

A 14-year-old boy was slightly injured in November when his 12-year-old friend brought a loaded .22-caliber derringer to Glendale Intermediate School, 1430 Andrew Ave., in Salt Lake City.

The gun was being shown to several friends inside a classroom when the 14-year-old injured himself when he shot one round into the floor and was hit by splinters of floor tile.

School and police officials said at the time of that incident that the gun did not belong to either the boy or a member of his family.