Federal prosecutors in the Michael Thomas case have moved to prevent the former Mashantucket Pequot chairman from defending himself against theft allegations by arguing that he intended to reimburse the tribe for personal expenses he charged to a tribe-issued credit card.

The trial is set to begin July 22 in U.S. District Court in New Haven.

"The Government anticipates that the defendant will claim that he acted in 'good faith' when he embezzled, converted or misapplied funds belonging to the Mashantucket Pequot Tribal Nation because he purportedly intended to return at some unknown date the funds he wrongfully obtained," prosecutors say in a motion filed Thursday.

Acting U.S. Attorney Deirdre Daly and Assistant U.S. Attorneys Christopher Mattei and Douglas Morabito signed the document.

Thomas, indicted in January on one count of theft from an Indian tribal organization and two counts of theft from an Indian tribal government receiving federal funds, allegedly stole more than $100,000 from October 2007 to September 2009. He served as tribal chairman from 2003 to 2009.

In a memorandum supporting their motion, the prosecutors say a defendant's "purported intent" to repay a victim of embezzlement is not a legally recognized defense and that therefore "any evidence in that regard is irrelevant."

They say they anticipate that Thomas will purse such a defense because Thomas, prior to the period charged in the indictment, repaid the tribe for personal expenses "he unlawfully charged" to an American Express card issued by the tribe.

"During any time in which funds were in the defendant's custody, they were not available to the tribal government to provide services to members, meet payroll, advance the organization's business, social or cultural interests, pay off debts or earn interest," the motion says.

Thomas' lawyer is Paul Thomas of the U.S. public defender office. The Thomases are not related.

b.hallenbeck@theday.com