National Republicans are again hammering Rep. Tim BishopTimothy (Tim) Howard BishopDem candidate 'struck by the parallels' between Trump's rise and Hitler's Dems separated by 29 votes in NY House primary Flint residents hire first K Street firm MORE (D-N.Y.) for being the subject of a congressional ethics investigation with a new television ad.

The ad, from the National Republican Congressional Committee, points to an investigation into whether the congressman’s office solicited a campaign contribution in exchange for securing permits for a constituent.

“Bishop did the favor, then got the cash,” a narrator says in the ad.

The narrator goes on: “Corruption, federal investigations. Tim Bishop is everything that’s wrong with Washington.”

A report out prior to the 2012 general elections revealed Bishop helped get environmental permits for a constituent hoping to launch fireworks at a birthday celebration. Before those permits were secured, however, Bishop’s aides allegedly reached out to the constituent and requested a campaign contribution.

Though Bishop has denied any wrongdoing and the constituent himself has called the issue a “nonstory,” the Ethics Committee is still reviewing the situation, and the FBI collected information on the case late last year.

Republicans believe the ongoing investigations have made Bishop, a perennial GOP target, the most vulnerable he’s ever been, and the NRCC has attacked him on the investigation in ads before.

Republicans George Demos, a former prosecutor with the U.S. Securities and Exchange Commission; and state Sen. Lee Zeldin are vying for the opportunity to take him on in the general election.