In a race that tends to be a snoozer, Democratic candidates for City Controller Alan Butkovitz and Rebecca Rhynhart exploded in shouting matches during a live-streamed forum Tuesday night.

"My opponent is so beholden to the political machine that he does not take the tough stances that I would make," said Rhynhart, a former top aide to Mayor Kenney and former Mayor Michael A. Nutter. It's an argument she has made against Butkovitz, a longtime ward leader, during the campaign.

"You think it was easy going after Sheriff John Green? I had to be assigned security guards because they thought I might be assassinated for the amount of corruption we found in there," said Butkovitz, who is running for a fourth four-year term, referring to an investigation of Green, who was indicted and awaits trial.

"I have the scars of fighting the political system for all the time I've been in office," Butkovitz said.

"You take things on when they are easy, not when they are difficult," Rhynhart shot back.

Tuesday's 70-minute forum, held in an office building at 230 S. Broad St., was hosted by the Committee of Seventy and the online publication Philadelphia Citizen. About 100 people attended the event, which was live-streamed on Facebook.

The forum was the last of two controller candidate debates held before the Tuesday primary. The first was April 27 at Springside Chestnut Hill Academy and included Republican Mike Tomlinson, who is unopposed.

Among the points of contention Tuesday were the city's expenses during the papal visit and the controller's duty in auditing all city departments.

Butkovitz criticized Rhynhart as not standing her ground over the $8 million payment the city made to the World Meeting of Families following the 2015 papal visit. Rhynhart, who was budget director at the time, has said she does not think the city should have paid that money, given the assurances made that taxpayers would not pay for the papal visit. Yet the city paid the $8 million, which covered nearly half of the total costs for the event.

Rhynhart said that while she protested the payment internally, it was Butkovitz who could have stopped the payment.

"Only one person could've stopped that payment, and that's my opponent. As controller, he could've stopped the payment, and he didn't," she said. "As city controller, I would've stopped that payment, yes, absolutely."

Butkovitz shot back that "there are court cases … that made it clear that the controller is required to spend money where there are contracts executed."

Rhynhart said she would find at least $10 million in savings each year by auditing every department, something she says Butkovitz does not do. He responded that his office audits every department. During a previous debate, he brought copies of the audit reports for various years.

The controller's website lists departmental audits. The most recent ones are from the fiscal year that ended June 30, 2015.

Butkovitz also said that he has averaged saving the city $10 million a year. In his 11 years in office, the city has implemented recommendations of his that led to $116 million in savings, he said.

On Tuesday, Rhynhart also announced that she is using $145,000 of her campaign funds to air a 30-second ad on cable channels and broadcast networks. The ad, which started airing Monday, attacks Butkovitz, calling him a "political hack," and tells voters change is needed and they should vote for Rhynhart.

Butkovitz campaign aide Maurice Floyd said his candidate also will be advertising on the air, but it was not decided when. "We're definitely going up," Floyd said.

Television ads are not common in controller's races. The most recent TV campaign was that of Brett Mandel, who ran against Butkovitz in the 2013 Democratic primary. Mandel said Tuesday that he spent about $60,000 on television ads. Butkovitz, who did not advertise on TV then, won the three-way Democratic race and the general election.

On Tuesday, Rhynhart's campaign released the results of an internal poll that showed most voters are still undecided in the race. The poll, by Normington, Petts & Associates, based in Washington, only asked voters if they were voting for Rhynhart or Butkovitz or if they were undecided, campaign spokeswoman Anna Adams-Sarthou said. The poll showed that 26 percent of the 500 voters polled would vote for Butkovitz, 23 percent would vote for Rhynhart, and 51 percent were undecided.

The poll, conducted by SEA Polling & Strategic Design, based in Florida, talked to 500 Democratic registered voters and indicated that if those polled were to vote that day, 32 percent would vote for Butkovitz and 23 percent would vote for Rhynhart. The rest were undecided.

Butkovitz said both polls were good news for him. "Rebecca's poll shows marked improvements in areas I used to struggle," Butkovitz said, referencing white voters which the poll showed him having 34 percent and Rhynhart 26 percent. "I really appreciate that and I'm excited."