You wouldn't expect at this point that a debate among the three Democrats running for Philadelphia city controller would be anything but a knife fight, and the face-off Thursday moderated by Comcast's Larry Kane, didn't disappoint.

"Right now, Alan Butkovitz is under investigation by the Ethics Board for violating the city's prohibition about using City of Philadelphia funds for political work," challenger Brett Mandel asserted early in the contest.

Mandel ran against incumbent Controller Alan Butkovitz four years ago, so at this point, these two guys know each other well.

Mandel said city controller staff produces materials Butkovitz has used at political events. Asked after the debate how he knew the Ethics Board was investigating, Mandel said someone he can't name told him the Ethics Board had contacted him. The board doesn't comment on investigations.

Butkovitz said he plays by the rules and is unaware of any investigation. Asked directly afterward if he'd been contacted by the Ethics Board, he said no, then added, "I mean, Brett is a smear artist par excellence. If Joe McCarthy was around, he'd have to doff his hat to Brett because Brett is the biggest smear artist in Philadelphia. He just says things."

Just another day at the office in the Democratic race for controller.

A familiar rumble

The campaign messages by Mandel and Butkovitz are, by now, well-defined. Mandel says Butkovitz, a Democratic ward leader, fails as the city's fiscal watchdog because he's compromised by political ties. Butkovitz says he's done aggressive audits and fought corruption, regularly infuriating powerful Democrats.

And Butkovitz says Mandel isn't quite the reformer he claims to be. He says in a meeting last year, Mandel offered to cut a political deal.

"Brett says, 'Look, I'm trying to think of a way that we can all be friends, and I've got two ideas. Here's idea No. 1: Why don't you not run for controller, support me, and you run for mayor and I'll support you?'" Butkovitz said at the debate.

Butkovitz said he told Mandel that was "a non-starter," and that Mandel then offered not to run against him if he would give Mandel a job as deputy controller.

Mandel acknowledged he met with Butkovitz, a sit-down arranged by Pa. Sen. Larry Farnese.

"Alan and I sat down. We talked about our ambitions," Mandel said. "I, of course, want to be city controller. He tells me he wants to be mayor. He tells me there's no way he's not running for mayor. We talked about what happens -- no deals, nothing came of it. We wasted an hour of my life. That's it."

You can read more about the conflicting versions of the meeting in this piece by the Daily News' Chris Brennan, who broke the story two weeks ago.

Butkovitz said he's looking at the 2015 mayor's race, but has made no commitments. In fact, he said in the debate he'd support City Council President Darrell Clarke should he decide to run. (Clarke has given no indication he'll run for mayor.)

And Zecca makes three

The third candidate in the race, Mark Zecca, did his best to distinguish himself from his squabbling rivals.

"They've been campaigning for six years," Zecca said. "Neither one of them is dealing with the fact that what we lack in the city government is internal controls by the finance department to stop the stealing, stop the corruption, stop the waste, stop the fraud."

Zecca cast himself as an independent who actually understands the workings of government from his many years as a city lawyer. He said Butkovitz should have been leaning on Mayor Michael Nutter's administration to transform the monitoring procedures in the city's finance office.

Butkovitz, Zecca said, had been nothing more than a "minor irritant" to the mayor.

After disputing Mandel's allegation that he was the subject of an Ethics Board investigation, Butkovitz had a charge of his own, asserting Mandel got web-design services that amount to an in-kind contribution in violation of the city's campaign finance limits. Mandel disputes that.

The primary election is May 21.

You can see the entire hourlong debate Sunday at 9 p.m. on the Comcast Network.