HARRISBURG -- The dispute over tuition that the Penn Hills School District paid for the children of U.S. Sen. Rick Santorum, R-Pa., to be educated via computer at their Virginia home has revealed a basic flaw in Pennsylvania's 2002 "cyberschool" law.

The district paid more than $100,000 for the three years that Santorum's five school-age children attended the Pennsylvania Cyber Charter School, headquartered in Midland.

Although the law requires school districts to pay for any resident students enrolled in a cyberschool, it does not explicitly say that applies to children from families who maintain a Pennsylvania residence but actually live outside the state.

Penn Hills has asked the state Education Department to review Santorum's case, although the department itself has not adopted any guidelines for such situations.

In the case of the Achievement House Charter School -- a cyberschool based in suburban Philadelphia that opened last fall -- the department advised school officials not to enroll a girl whose parents owned a Pennsylvania home but spent most of their time doing missionary work in Kenya, according to the school's administrator Wallace H. Wallace.

Rep. James Roebuck, the ranking Democrat on the House Education Committee, said lawmakers need to clarify which students may enroll in a cyberschool at taxpayers' expense.

"Taxpayers have enough of a responsibility for trying to educate kids who are bona fide, legitimate residents," the Philadelphia legislator said. "They shouldn't have to be paying for kids who aren't residents of that district."

The Penn Hills school board contends it should not have had to pay the Santorum children's tuition because the family actually lives in Virginia, even though the senator and his wife also own a house in the district.

The Pennsylvania Republican's children had been enrolled in the school since the 2001-02 school year.

In November, amid publicity about a school board member's criticism of the arrangement, Santorum agreed to withdraw his children from the cyberschool and resume homeschooling them.

Neither the cyberschool nor the senator has offered to reimburse the school district, and Santorum has said he did nothing wrong.

Nick Trombetta, the cyberschool's chief administrative officer, said Santorum produced valid documentation of his Penn Hills residency, including his driver's license, when he enrolled the children.

"It didn't go under the radar at all," Trombetta said.

But Penn Hills school board member Erin Vecchio said Santorum has never lived in the district, despite owning a two-bedroom house that was assessed at $106,000 last year. His nearly four-acre property in Leesburg, Va., was assessed at $757,000 this year, according to tax records.

"We never even knew they attended the cyberschool," Vecchio said.

Vecchio said she believes a 2000 state Supreme Court decision made clear what constitutes residency.

The court ordered the Cumberland Valley School District to cover the tuition of a boy who attended a private school for disabled children in Montgomery County, even though his mother maintained a second home in another school district. The justices concluded the family were Cumberland Valley residents because they "stay there during the days and sleep there at night."

Although there is no case law specifically involving residency standards for cyberschool students, an attorney for the Pennsylvania School Boards Association said they would likely be similar to those that apply to other public school situations.

"It would be a difficult read to try to say that residency is different for cyberstudents than for other people," said the lawyer, Emily Leader.

Rep. Jess Stairs, chairman of the House Education Committee, agreed.

"I think the residency question is something that should be resolved," he said. "I would hope we can look at it again."

But Erik Arneson, an aide to Senate Majority Leader David Brightbill, of Lebanon County, said he sees no urgency to revisit the law because it "clearly lays out a process for determining residency."

"Given the fact that this is an isolated case ... we think the law is working as intended," Arneson said.