Federal authorities are investigating a 2010 land deal for a Vermont college that was run at the time by Jane Sanders, the wife of Senator Bernie Sanders of Vermont. The deal ultimately contributed to her ouster as president of the college.

The deal involved a $10 million sale of about 33 acres of lakefront property by the Roman Catholic Diocese of Burlington to Burlington College — where Ms. Sanders was president — so the college could relocate and expand.

To finance the purchase, the college needed to borrow from a bank and obtain additional financing from the diocese, according to David V. Dunn, a Burlington College trustee at the time.

A public agency issued a bond, which the bank then bought. The college needed to demonstrate that it had the financial resources to pay the bank loan, which it did by saying that it would receive $2.6 million in donations and that it would also increase its enrollment, Mr. Dunn said. “Neither of those were true,” he said in an interview Monday.