A school bus driver will face kidnapping charges for taking 13 students on a 115-mile detour, a rifle by his side.

In federal court in Philadelphia, Otto Nuss, 63, was ordered to undergo a psychiatric evaluation and to be held without bail until a hearing next week. Asked about his mental competency, public defender Felicia Sarner said: "I think there are clearly issues that need to be developed here."

Nuss surrendered on Thursday outside Washington D.C. in Landover Hills, Md. after a six-hour trip where he told the students he was taking them on a "field trip" to the city instead of their religious school in Pennsylvania. A search of the bus turned up 75 rounds of ammunition.

Later, police found 48 weapons in Nuss' house, including a dozen handguns.

At a hearing before a federal magistrate earlier Friday, questions arose about Nuss' ability to understand the proceedings. The magistrate asked Nuss whether he suffers from mental illness.

Nuss replied, "No sir, I'm not insane."

When asked if he understood the case against him, Nuss said: "I'm not totally involved in it, is what I'm saying."

Earl Derr, a longtime friend of Nuss, said Friday he had taken Nuss for psychiatric help in the 1970s and that Nuss had admitted himself to a hospital. Derr said Nuss had taken prescribed medication since then, but told Derr in November that the doctor said it was okay to stop using it.

"I think he got off his medication, and it just worked on his nerves," Derr said.

Berks Christian School officials said this was Nuss' first year as a bus driver and that Nuss had passed criminal background and child-abuse checks. Mental health history is not reviewed in either check.

Nuss had worked at Mrs. Smith's Bakeries in Pottstown for 42 years, working his way to foreman, until the pie plant closed in 1998.

Public defender Daniel Stiller said after the hearing that Nuss believes that he is not totally responsible for bringing the children to Maryland and that there was a "setup." Stiller refused to elaborate.

"It's a sad case, not a sinister one," Stiller said.

Ness had picked up the students, ages 7 through 15, in Oley, Pa., on Thursday morning for their daily six-mile trip to the Berks Christian School in Birdsboro. After the bus failed to arrive at school, a frantic search began along the route. 

"It just didn't seem like he was kidnapping us," said ninth-grader Tyler Rudolph, 15. "He told us we all needed a wake-up call and that we were going to learn something. And he was going to learn something, too."

"He never touched anybody," said eighth-grader Josh Pletscher, 13. "We were having fun."

Nevertheless, according to court papers, one of the students drew "911" on a fogged bus window.

Pletscher said that Nuss never touched the gun and that when a child noticed it, Nuss said it was "a symbol to bin Laden."

The Associated Press contributed to this report.