BANGOR, Maine — Troy Jackson, the Democratic candidate for Senate, directly challenged Susan Collins' denials of a ProPublica report alleging a pay-to-play scheme involving the Republican incumbent.

"We deserve answers about every contract and every conversation that Collins and her team facilitated on the backs of taxpayers," Jackson said at the Maine Democratic Nominating Convention on July 25. "The jig is up."

Jackson, a former Maine Senate president, said the ProPublica investigation was detailed and factual. "Those are all facts," he said of the reporting.

The ProPublica report centers on an alleged pay-to-play probe involving Collins. Collins and her staff have denied the allegations. An aide called the report "categorically false," and Collins herself described it as "completely false."

The exchange underscores the intensity of the race for Maine's Senate seat, where Democrats are targeting Collins as a potential pickup.

Jackson also criticized Collins for a campaign statement in which she mentioned that the mother of his children is his second cousin, calling it a personal attack on his family.