The Authority is not dealing with the same tribal officials who were involved with the questioned invoice, Bonderud said.

“They may not understand what happened. We’re going to talk to them, sit with them and the DNRC and the Authority, and demonstrate to them when and how this occurred,” he said.

A meeting of state, Authority and tribal officials to review the state’s documents regarding the overbilling is tentatively scheduled for later this week in Helena.

CCCC officials could not be reached for comment.

In June 2010, the state authorized reimbursement of a vendor contract that included a pipe-shipping expense of $495,000. Upon review, the actual shipping cost was $349,000, leading to a $146,000 overpayment, Tubbs said.

The DNRC started reviewing its books as soon as it learned of the federal corruption investigation and worked with an attorney in the state Department of Justice’s Division of Criminal Investigation and with federal investigators, he said.

The T. Consulting invoice was provided to the DNRC by federal officials during the state’s internal investigation, said John Grassy, DNRC spokesman. The DNRC, he said, “did not receive the invoice as part of its authorized role in the project funding.”