Bill Walczak will air the first negative attack ad of the Boston mayoral race during the televised debate, and it will continue to appear on cable and network TV in the market area, according to a report by the Boston Herald.

Walczak has been consistent throughout the race regarding his disapproval of a casino in the city of Boston. Walczak’s ad features a voice-over of the candidate vowing to stop a casino from coming to the area.

The ad targets Charlotte Golar Richie, Marty Walsh, Mike Ross, Felix Arroyo, Rob Consalvo and Charles Yancy as supporters of a casino in Boston.

Walczak’s ad points the finger at John Connolly and Dan Conley for their lukewarm, undecided stance: “These two candidates can’t make up their minds,” Walczak’s voiceover says.

Recently, Conley accused the five city councilors in the mayoral race of “ducking” a move to allow the entire city to vote on a casino project, according to the Boston Herald.

With both Conley and now Walczak starting the attack process, the stage is set for the much-anticipated and consequential debate, that will air in primetime tonight from the Suffolk University’s Modern Theatre.

The event, co-hosted by the Boston Herald will feature all 12 mayoral candidates. The debate will air on NECN and stream live on bostonherald.com starting at 8 p.m.