As a protracted and increasingly heated Republican primary contest continues in the first Congressional District, the national GOP is slamming incumbent Rep. Tim Bishop.

In a TV ad unveiled on Thursday, the National Republican Campaign Committee returns to the ethics controversy surrounding Bishop’s efforts on behalf of a constituent to secure a fireworks permit and a subsequent campaign contribution.

Bishop, who was investigated by the House Ethics Committee over the matter, donated the contribution to charity.

Still, Republicans have repeatedly knocked the Suffolk County Democrat over the incident.

Sen. Lee Zeldin and former SEC prosecutor George Demos are the Republicans vying for the nomination to take on Bishop in the June congressional primary.

Here is the ad’s script:

Here’s the story on Tim Bishop: Bishop agreed to help a constituent obtain government permits. Then days later asked for thousands in cash. Bishop did the favor, then got the cash. FBI agents have investigated Bishop’s actions. An ethics panel found substantial reason to believe he committed a crime. Corruption, federal investigations. Tim Bishop’s everything that is wrong with Washington.