New Haven - A federal prosecutor told jurors in Michael Thomas' theft trial Wednesday morning that the former Mashantucket Pequot tribal chairman used a tribe-issued credit card as "his own personal piggy bank" in embezzling about $100,000 from the tribe from 2007 to 2009.

Following closing arguments, jurors began considering the evidence in U.S. District Court.

Thomas' public defender characterized the case against his client as "guess work," telling jurors the government had failed to prove its case.

"What you have here is opinions, belief and assumptions -- and that's not proof, let alone proof beyond a reasonable doubt," Paul Thomas, who is not related to Michael Thomas, said.

Testimony during the trial showed Thomas had used a tribe-issued American Express card to pay a limousine service nearly $90,000 to transport his ailing mother to dialysis treatments three times a week, and to purchase computers, Internet and cellphone services and for cable television and satellite radio.

Paul Thomas said the government could only assume the charges, except for a handful of minor exceptions, represented personal expenses. He suggested his client's mother, who died in 2010, was entitled to medical transportation that the tribal government routinely provided to tribal members but was ill-equipped to supply in her case.

"Does any public official need to be told they can't use government money for personal and family expenses?" Assistant U.S. Attorney Douglas Morabito asked jurors. "It defies common sense that Thomas didn't know what he was doing was wrongful."