Updated

A Connecticut Democrat’s bid for a U.S. House seat has been thrown into turmoil as the result of purported, illegal campaign contributions that resulted in undercover FBI agents infiltrating a state party convention.

The investigation involves the campaign of Christopher G. Donovan -- the state assembly’s House speaker who is running for a 5th Congressional District seat.

Chief Donovan fundraiser Robert Braddock Jr. allegedly had been trying to conceal $20,000 in campaign contributions, given in exchange for killing an assembly bill that would have increased taxes on roll-your-own-cigarettes stores, according to the Connecticut Post.

The agents attended a May 14 convention of state Democratic delegates to endorse a candidate for the 5th District seat, perhaps looking to see whether those thought to be involved in the purported deal were talking to one another.

The tax-increase legislation never received a full assembly vote and died May 9, the end of the 2012 session.

Braddock has been arrested. Donovan has so far not been implicated, and his campaign has launched an outside investigation.

Click to read more from the Connecticut Post.