Donovan said he had hired an attorney and enlisted a former U.S. attorney to perform an internal review and hand over the results of that review to prosecutors. He said he would not resign as Speaker of the state House.

Donovan faces two other Democrats — Elizabeth Esty and Dan Roberti — in the primary set for Aug. 14, but has already secured the endorsement of the state Democratic Party. A crowded field of Republicans is vying for their party's nomination for the seat.