A graphic arts teacher at a Blair County vocational-technical high school has been charged with luring a South Hills teen to meet and have sex with him after encountering the girl last year in an Internet chat room.

West Mifflin police arrested Dirk Ormsby, 49, of Altoona, this month after breaking up an afternoon encounter between him and a topless 16-year-old girl in a pickup truck outside Century Square shopping mall.

Investigators later learned that the encounter was not their first and that they had been meeting over the past seven months, Police Chief Frank Diener said.

Ormsby, who teaches digital printing at Greater Altoona Career and Technology Center, was being held in the Allegheny County Jail on $60,000 cash bond.

He was arrested April 9 after West Mifflin Officer Greg McCulloch, patrolling outside the mall at 1:48 p.m., spotted the parked truck and saw two people partially lying inside, Diener said. He also noticed that the drivers of other vehicles were passing by and peering into the truck and that the girl inside was topless, the chief said.

McCulloch parked beside the truck and found Ormsby lying across the seat and the girl sitting on the passenger side. After informing them that people had been watching their activities, he noticed that the girl looked "very young" and asked her age, Diener said.

Initially the girl told police she was 18, but later admitted she was 16. McCulloch arrested Ormsby for disorderly conduct and corruption of minors.

After questioning both and investigating further, police learned that Ormsby and the girl became acquainted months earlier in an Internet chat room and that they had been meeting regularly since then, Diener said. Police then filed additional charges of involuntary deviate sexual intercourse, aggravated indecent assault, indecent assault and unlawful contact with a minor against Ormsby.

Police consider the girl to be "a complete victim" and have released her to her parents, Diener said. They also asked state police to obtain a search warrant to seize and check the contents of Ormsby's computers.

He would not comment on whether investigators believe Ormsby had contact with other underage girls, but said, "We are continuing this investigation because we believe we have good reason to do that."

State troopers this week seized two computers from the Altoona school where Ormsby has taught for 14 years. The school provides training classes for students from seven Altoona-area school districts.

School Executive Director Lanny Ross said he was surprised by Ormsby's arrest, saying he had been a respected faculty member in good standing. The school's joint operating committee -- its version of a school board, made up of representatives from participating districts -- will review the matter next week, Ross said.

"Hopefully we'll have Mr. Ormsby's resignation by then," he said. "If not, we'll be forced to take another course of action."