An 11th grader purportedly despondent about his grades brought a rifle to Springfield High School in Montgomery County this morning, fired high into a wall to frighten other students into a hallway, and then shot himself to death, witnesses and officials said.

No one else was injured, authorities said.

Police converged on the school, on Route 309 in Erdenheim, following reports about 9 a.m. of gunfire inside the school. The building was in lockdown for more than an hour, said Laura Feller, a school district spokeswoman.

Students and parents at the school identified the student as Shane Joseph Halligan, 16, of Oreland.

Montgomery County District Attorney Bruce Castor told reporters at a late afternoon news conference that Halligan died after putting the barrel of the AK-47 semiautomatic rifle under his chin and firing.

Castor said that a suicide note was found in the right front pocket of Halligan's jeans and that the suicide followed an argument with his parents Monday about falling grades on his report card.

"He felt that things he saw as important in his life were being taken away from him," Castor said.

Castor said that Halligan was told by his parents that if his grades did not improve he would have to cut back his hours as a volunteer fireman and would not be allowed to go to National Guard boot camp next summer.

The gun used in the suicide, Castor said, was one of "multiple guns" Halligan's father kept in a cabinet in the back of a closet locked with two keys. Castor said the student stole the keys Monday night to unlock the cabinet and take the rifle.

At an earlier news conference, Springfield Township Police Chief Randall Hummell said school security cameras captured Halligan removing a rifle from a gym bag while other students were in the area.

The cameras did not record the shooting, police said. Some students reported hearing the gunfire and others described confusion that followed.

Senior Michael DeLaurentis, 18, said he witnessed the initial shot in the hallway outside a second-floor science lab but did not get a good look at the gunman because the student was not facing him.

"It's the most crowded hallway in the school," he said. "I saw him shoot in the ceiling and I heard him yell, 'Get down!' So I don't think he was trying to hurt anyone."

After the shots were fired - authorities said the bullets actually struck high on a cinder-block wall - "everyone just started screaming and sprinting outside," DeLaurentis said.

About 1 p.m., Halligan's father, John, spoke to a group of reporters outside the family home, a two-story Colonial on Integrity Avenue that was trimmed with holiday decorations. He said that someone else in the family had recently gone through a serious illness but that there was no indication his son had been troubled.

John Halligan said he and his son watched a football game last night and he and his wife, Donna, were home this morning when Shane, an Eagle Scout, grabbed his backpack and said his usual goodbye.

When asked by reporters, Halligan didn't comment on whether he saw his son with a gym bag but said that "the weapon was kept under lock and key."

"We see this on the news and wonder how it could happen. It doesn't happen in our family," Halligan said, his voice breaking. "... I'm at a loss."

At the earlier news conference, school superintendent Roseann Nyiri called the suicide a "very, very sad situation." Counseling was being made available to all high school students in the middle school's cafeteria.

It was the second gun episode and lockdown at Springfield High this fall. On Sept. 21, a student was arrested after showing a loaded gun to another student in a restroom.

The school again made news during a subsequent Inquirer investigation of security at dozens of area schools. Despite a sign that read, "Doors must remain locked at all times," a reporter was able to walk in, pass scores and students, and even go unchallenged by two security guards.

Malcolm Gran, vice president of the Springfield school board, said that he was at the school all day after hearing about the suicide. "Our superintendent, our faculty and our students did an amazing job, under the circumstances," he said. "The students responded amazingly - the teachers knew what to do."

Asked whether he believed that the school district had the proper safety precautions in place, Gran said, "The reality is, when someone wants to commit suicide... God knows how it can be prevented."

Gran said the district has been reexaming school safety issues after earlier incidents, adding, "I was satisfied as of yesterday [before the suicide]; I will want to hear more about what happened today."

Gran said, however, that he was still undecided about installing metal detectors in the high school.

The school has no metal detectors, although installing them has been considered. Nyiri said the September gun episode was considered an isolated incident.

When asked about security at the school, school board member Anthony McDowell, whose daughter is a senior at the high school, said: "I'm letting the people whose job it is - the professionals - deal with it right now. Once the findings come out, we'll look at it and address whatever issues there are. We do have plans in place to deal with the direction this society is, I guess, moving in. I'm sure, as more information comes out, we will be taking additional steps."

DeLaurentis described Shane as a short, intelligent boy. DeLaurentis' father, also named Michael, said Shane came from "such a great family." He described the boy's mother as "the sweetest person." The boy's father, he said, had done landscaping work and was "a very hard-working guy."

By midday today, friends were leaving notes on Halligan's page. "Rest In Peace friend im sorry it ended like this," one note said.