COLUMBIA, S.C. -- South Carolina's top accountant is accused of using campaign money to accompany his girlfriend to the Republican National Convention last year.

The state Ethics Commission found probable cause last month that Comptroller General Richard Eckstrom violated state ethics law. He faces six charges of using campaign money for personal benefit, according to documents obtained Thursday by The Associated Press.

Under state law, ethics complaints stay secret until probable cause is found.

The 65-year-old Republican, first elected to the office in 2002, reported spending $1,642 in campaign money for gasoline, food and the hotel stay during the GOP convention in Florida in August 2012. Eckstrom's girlfriend was an alternate delegate.

His chief of staff, Eddie Gunn, points to a section of state law specifying that travel expenses connected to a political event can be paid out of campaign coffers.

"It's mystifying that they're not being regarded as permitted political expenses," he said. "Very clearly, this is a political event."

But ethics director Herb Hayden said Eckstrom was not at the convention in any official capacity. He attended functions using his girlfriend's guest pass, he said.

State law allows campaign money to be used for expenses directly related to a campaign or for normal office expenses.

"Taking a vacation with your girlfriend is not a regular expense of the office," Hayden told the AP. "If he had been a delegate and there in his official capacity - if he went because he was state comptroller general - it would be a different situation. But he would not have gone had she not invited him, according to our investigation."

A hearing is scheduled March 9. By law, it will be closed to the public unless Eckstrom asks that it be open. Gunn said he was unsure whether Eckstrom would request that.

Possible penalties include up to $2,000 per offense and a public reprimand. State law allows for ethics fines to be paid from campaign cash.

According to Eckstrom's October 2012 campaign disclosure, he spent $1,372 at Innisbrook Resort in Innisbrook, Fla., during the convention. Other reported expenses were three stops for gasoline totaling $238 and two meals costing $32.

Eckstrom, state treasurer from 1995 to 1999, is expected to seek a fourth term as comptroller general in 2014. He had nearly $126,000 cash available as of his latest campaign filing in October.

It is not the first time Eckstrom has been under scrutiny for a trip.

During the 2006 campaign, Eckstrom reimbursed the state $669 for taking a state minivan and paying for fuel with a state-issued gas card on a 2004 family vacation to his native Minnesota, which he called a "mistake in judgment." The state Ethics Commission investigated and found no wrongdoing.