PIERRE - Despite a call for an investigation into how South Dakota spent some federal transportation money, an official from the state Legislative Audit office says the state did nothing wrong.

U.S. Rep. James Oberstar, D-Minn., says South Dakota did not have authority to spend $1.5 million on a state plane in 2005. The plane is used by Gov. Mike Rounds.

The money was supposed to be used for Amtrak, intercity bus lines or airline services.

The congressman says purchase of the state plane did not qualify as an approved use of the funds.

But Gary Hoscheid of the Legislative Audit office says the issue has been scrutinized by that office and officials do not believe the state misspent the money.

"When we did a review of the transaction, we found no violation of state or federal rule, law or regulation," Hoscheid said.

The state received $23 million from the federal government in 1997 as part of $2.3 billion in tax refunds given to several states.

Oberstar, who chairs the U.S. Committee on Transportation and Infrastructure, sent the U.S. Inspector General's office a letter in which he claimed that when South Dakota spent some of the money on an airplane it was "in violation of the express purposes for the funding."

Information about how the money was spent is stated to have come from the Legislative Audit Office.

If the inspector general decides to study the airplane purchase, there is no way of knowing how long it may take, said Mary Kerr, a staffer on the congressional committee.

"It could take a year," Kerr said. "We don't give them a time frame and this sort of thing takes quite a while."