4 Dead in Amish School Shooting in Pa.

In this image made from video, residents gather together in Nickel Mines, Penn. on Monday, Sept. 2, 2006 after a 32-year-old truck driver took more than a dozen students hostage in a one-room Amish schoolhouse, barred the doors with boards and fatally shot at least six people, authorities said. (AP Photo/WTXF TV) MANDATORY CREDIT: WTXF TV; NO SALES (AP)

NICKEL MINES, Pa. -- A milk-truck driver carrying three guns and a childhood grudge stormed a one-room Amish schoolhouse Monday, sent the boys and adults outside, barricaded the doors with two-by-fours, and then opened fire on a dozen girls, killing three people before committing suicide.

At least seven other victims were critically wounded, authorities said.

It was the nation's third deadly school shooting in less than a week, and it sent shock waves through Lancaster County's bucolic Amish country, a picturesque landscape of horse-drawn buggies, green pastures and neat-as-a-pin farms, where violent crime is virtually nonexistent.

Most of the victims had been shot execution-style at point-blank range after being lined up along the chalkboard, their feet bound with wire and plastic ties, authorities said. Two young students were killed, along with a female teacher's aide who was slightly older than the students, state police Commissioner Jeffrey B. Miller said.

"This is a horrendous, horrific incident for the Amish community. They're solid citizens in the community. They're good people. They don't deserve ... no one deserves this," Miller said.

Miller told Fox News late Monday that a fourth girl had died at Hershey Medical Center. However, a spokeswoman for the hospital, Amy Buehler Stranges, said that there had been no change in the condition of the three girls at that hospital.

State police spokeswoman Trooper Linette Quinn said Miller's information had come from crime scene investigators, and she could not explain the discrepancy.

The gunman, Charles Carl Roberts IV, a 32-year-old truck driver from the nearby town of Bart, was bent on killing young girls as a way of "acting out in revenge for something that happened 20 years ago" when he was a boy, Miller said.

Miller refused to say what that long-ago hurt was.

Roberts was not Amish and appeared to have nothing against the Amish community, Miller said. Instead, Miller said, he apparently picked the school because it was close by, there were girls there, and it had little or no security.

The attack bore similarities to a deadly school shooting last week in Bailey, Colo., but Miller said he believed the Pennsylvania attack was not a copycat crime. "I really believe this was about this individual and what was going on inside his head," he said.

Miller said Roberts was apparently preparing for a long siege, arming himself with a 9mm semiautomatic pistol, a 12-gauge shotgun and a rifle, along with a bag of about 600 rounds of ammunition, two cans of smokeless powder, two knives and a stun gun on his belt. He also had rolls of tape, various tools and a change of clothes.