SALTSBURG, Pa. (AP) — A western Pennsylvania high school shop teacher raped a 16-year-old student at school last year, state police said, and their investigation into him continues because it began with a recent complaint from another student about unwanted attention from him.

That complaint surfaced last week, and school officials and the police eventually learned that Todd McCullough, 28, of Kiski Township, raped a Saltsburg High School student in the spring of 2012, police said.

Before the assault, McCullough allegedly made inappropriate comments to the girl, authorities said.

"On one occasion, the accused told the victim that she was looking 'hot' and that his girlfriend was going to be away this weekend," police wrote in the criminal complaint.

Another time, McCullough allegedly complimented the girl on her tan and asked to see her breasts. McCullough then took the girl to a closet area and exposed himself to her, only to apologize days later.

Some days after that, McCullough had the girl taken out of another class and raped her in a private room of the shop class area of the school, police said.

Police haven't listed a date for the rape but said the girl recalls it occurred about the time of last year's prom.

McCullough doesn't have an attorney and declined to comment after his arraignment Thursday on rape and related charges. He remained in jail unable to post $150,000 bond pending a preliminary hearing Nov. 13.

The probe started with accusations that McCullough made inappropriate statements to another female student, authorities said. That investigation eventually led to the rape charges, which the accuser had previously revealed only to a friend, police said.

Troopers from the Indiana, Pa., barracks consider the investigation "intense and ongoing."

"This could be the initial phase of a significant investigation, and we won't rule out the possibility of additional charges or additional victims," Trooper John Matchik, the barracks' spokesman, said.

The Blairsville-Saltsburg School District issued a statement saying officials are cooperating with the investigation and, while not naming McCullough, said an internal investigation suggests the employee has violated district policies and state laws.

Saltsburg is about 30 miles east of Pittsburgh.