HARRISBURG, Pa. (AP) — Improper lease reimbursements to charter schools may have cost state taxpayers millions of dollars, Pennsylvania's newly elected fiscal watchdog said Thursday.

State Auditor General Eugene DePasquale released audits of six charters that cited improper lease reimbursements totaling more than $550,000 over multiple years — mostly involving buildings leased from organizations with direct ties to the schools.

"The charter school law was established to provide students and parents with publicly funded education alternatives," he said at a Scranton news conference. "The charter schools are funded by tuition payments from school districts and should be focused on providing the best possible education for students, not looking for additional revenue streams funded by taxpayers."

DePasquale said his office focused on the issue in its ongoing performance audits because a 2010 review of Philadelphia charter schools by the city controller's office turned up similar problems. As part of the state audits, officials traced the ownership of property leased to the charter schools by inspecting the deeds on file in each county, he said.

The cost to state taxpayers could escalate to millions of dollars if the practice turns out to be widespread among Pennsylvania's other privately run, publicly funded charter schools, DePasquale said.

Currently, there are 159 "bricks-and-mortar" charter schools and 16 Internet-based cyber-charter schools operating in Pennsylvania, according to the state Department of Education.

The audits released Thursday focused on charter schools in Lehigh, Luzerne, Lackawanna, Mercer, Bucks and Monroe counties.

DePasquale, who took office in January, said he hopes to work with the Corbett administration and the charter schools to resolve lease-reimbursement problems and other issues.

Education Secretary Ron Tomalis is aware of the audit findings and will review them, his spokesman Tim Eller said. A message left for the Pennsylvania Coalition of Public Charter Schools was not immediately returned.