In a debate at the KPBS studios, City Councilman Carl DeMaio, District Attorney Bonnie Dumanis, Rep. Bob Filner, D-San Diego, and Assemblyman Nathan Fletcher took questions from a panel that included 10News anchor Kimberly Hunt, U-T San Diego reporter Craig Gustafson and KPBS reporter Katie Orr.In their opening and closing statements, the candidates delivered the messages that have defined their campaigns to this point."I'm running for mayor because it's time to finish the job of fiscal reform and get back what we've lost over the past decade -- our road repairs, our neighborhood services," said DeMaio, who has consistently led the polls. He positioned himself as someone who has stood up to City Hall insiders over the years.Dumanis touted her experience as a chief executive of a major agency making tough decisions."We're at a critical moment, right now, in our city's history," Dumanis said. "This office is too important to trust to someone whose never made the kind of decisions that I have."Filner said he would fight for neighborhoods and middle-class residents."You've got to represent all the neighborhoods, you have to give all the people in this city economic and political power," Filner said. Too few people have been involved in making important decisions at City Hall, he said.Fletcher, who recently left the Republican Party to become an independent, said he would bring a new voice to city leadership."I believe to advance where we want to go to become the world's most innovative city, to rebuild our economy, our education system and our city, it's going to take something new," Fletcher said.Fletcher also harkened back to his interrogation of al-Qaida while a Marine, saying he could certainly negotiate for a new football stadium. The discourse was civil, for the most part. Sparks threatened to fly when DeMaio asked Fletcher, "Are you under investigation for an ethics violation?""Yeah, as usual Carl, your facts are off, we're not under any investigation by the [San Diego] Ethics Commission," Fletcher said. He said it was ironic that DeMaio would ask the question, and levied an oft-repeated charge that the councilman tried to defund the panel after he was fined.10News learned a complaint had been lodged, but the Ethics Commission dismissed the matter because there were not enough sufficient facts to back up the complaint and that it was based on speculation. DeMaio earlier contended that Fletcher was running a "negative campaign."Dumanis pressed Filner for proof that his pension reform plan would save the city money, since he opposes Proposition B -- a citizen's initiative to restructure the retirement system for municipal employees."Bob, where is the proof of savings in your plan? That's why we want to see a plan," said Dumanis. Filner said the proposition was "a fraud" that won't save money. He said he would negotiate a five-year deal with the city's unions, stop six-figure pensions, refinance debt in the pension system,Filner bristled at a question raised by Gustafson. "My plan, as I said, I cap pensions, I refinance and I negotiate a five-year labor pact. Is there something you're missing there, Craig?" Fletcher was questioned about becoming an independent, and one audience member loudly grumbled at one of the Dumanis' answers. It was a spirited debate, as illustrated by the following exchange: Fletcher: "Back to yes or no on transparency. Have you met with lobbyists funding your campaign behind closed doors? Direct answer: yes or no?" DeMaio: "I will meet with anyone who has ideas on cutting costs at city government." Following the debate, Fletcher's campaign manager Matt David said of DeMaio's Ethics Commission question, "This is an outrageous political stunt cooked up by the DeMaio campaign. It was dismissed without merit.""Who did they work with to cook up this complaint?" asked 10News reporter Vanessa Van Hyfte."DeMaio knew this complaint had been dismissed for over a week, yet he intentionally tried to mislead voters," David replied.A representative from DeMaio's campaign said, "We did not file the complaint, but we were in communication with the person who did file"If no one wins a majority vote in the June 5 primary, the top two vote-getters will square-off in November.