A mayor's race that began with high-minded debates and polite candidate forums has degenerated in its last hours to harsh personal attacks between the two perceived front-runners.

While Tom Knox depicted Michael Nutter as a compromised political insider, Nutter railed against Knox as "a scumbag." Nutter made the comment after flyers were distributed outside at least two Catholic churches early yesterday accusing Nutter of changing his religious beliefs for political reasons.

It was a sharp departure from a day in which all but one of the five candidates vying for the nomination in tomorrow's Democratic primary acted in typical candidate fashion: scouring the city, especially its voter-rich African American churches, for votes.

"Remember that Democrat Tom Knox is a practicing Catholic," the flyer reads. "Michael Nutter? He was Catholic when it was convenient for him, so he could get a quality Catholic education. Now? He quietly left the Catholic Church to become a Baptist, probably because his polls told him it would be a smart move."

The flyer had a red headline and Knox's name at the bottom in red, but there was nothing on it to indicate who was responsible for the literature. It was placed on car windshields outside at least two Catholic parishes in opposite ends of the city.

Asked about it as he left Waters AME Church in Bella Vista, Knox said he was unfamiliar with the flyer. "Believe me, it's not me doing that - there are some things you just don't do," he said, adding that it was wrong to attack somebody's religious practices.

Nutter, 49, was raised Catholic but started attending Baptist churches in the mid-1980s.

"It's clear to me, based on the other filthy literature Tom Knox has been mailing out, that this is clearly more of his nasty tactics," Nutter said, brushing off Knox's denial.

Then, standing in front of the Philadelphia Zoo, where he had gone to meet voters, Nutter put both hands in his pants pockets and calmly disparaged Knox in the most brutal language of the campaign.

"Tom Knox is a low life and a scumbag for being associated with this kind of vile, vicious kind of literature," he said. "It is an absolute insult to all churchgoers and Christians that this kind of literature is handed out in front of churches. All we are left to ask is this question: Tom Knox, have you no dignity?"

Bob Brady was also attacked in the flyer. In interviews, Brady has described himself as a regular churchgoer.

"Bob Brady? He admitted that he never attends Mass," the flyer said.

Yesterday, holding up his hands and shaking his head, Brady would not address the issue. "I'm not going to respond to Tom Knox," he said.

Knox has stuffed mailboxes citywide with literature terming Nutter a "failed politician" and insider who was on the payroll of a company with a city contract, although Nutter had by then resigned his Council seat.

"He's part of the problem," is the tagline on one flyer. Another piece is bordered by yellow crime-scene tape and shows increasing crime statistics from Nutter's former fourth councilmanic district.

Asked about his attacks, Knox said he was defending himself. Nutter has launched a television ad quoting newspaper editorials that say Knox is unprepared to be mayor, accompanied by unflattering black-and-white video of the candidate looking downcast. "He's doing the same thing to me," Knox said.

His campaign believes Knox has been criticized often in the media while Nutter has had much less scrutiny.

Knox also said that Nutter was not a true reformer because of his "alliance with Vince Fumo and Bob Brady." He was referring to indicted State Sen. Vincent J. Fumo, a South Philadelphia powerbroker who helped persuade Brady to run.

Knox has said in recent days that Brady, who has stalled in the polls, was planning to throw his support to Nutter to save his Democratic chairmanship and stop Knox. Brady has denied such a deal exists, and yesterday Nutter did too.

"There is absolutely no deal," Nutter told reporters outside La Mott AME Church on Cheltenham Avenue. "There is nothing."

The Catholic flyer was not the only anonymous hit piece directed at Nutter. A flyer printed on plain white paper has been circulating since Saturday in parts of West Philadelphia, attacking Nutter's proposal to direct police to stop and frisk people suspected of carrying illegal guns in high-crime areas.

The piece features a famous 1970 news picture of police lining underwear-clad men suspected of being Black Panthers against a wall. "A vote for Nutter is a vote for racial profiling," the piece says.

Otherwise yesterday, all but Dwight Evans spent some of the day attending religious services. "This may be my last church stop in my campaign for mayor - and let me tell you, I had a lot of church," Brady said to about 75 congregants at Christian Tabernacle Baptist Church in North Philadelphia. Brady also visited some parading Mummers yesterday and met residents at a Center City apartment.

"Bobby's going to win, there's no doubt about it," said Cyprian P. Anyanwu, a member of Christian Tabernacle who also runs a local campaign office for Brady. "The fact of the matter is this is a man who is neither black nor white. This man is an open, simple individual."

Evans remained out of sight for much of the day, after an all-night tour that included a 2 a.m. stop for cheesesteaks at Pat's and Geno's; a 4 a.m. stop at the Oregon Diner; a 5 a.m. stop at the Melrose Diner; and the candidate's annual get-together breakfast at the Oak Lane Diner at 9 a.m.

Fattah hit three churches, had a Mother's Day celebration with his family at an Old Country Buffet restaurant, and attended a ceremony honoring his mother, community activist Falaka Fattah.

"If this city is going to rise to the potential that God has created for our city, our citizens are going to have to be lifted up," Fattah said from the pulpit of Greater Exodus Baptist in North Philadelphia, standing up for his plan to fund antipoverty programs by leasing Philadelphia International Airport to private enterprise.

He said his campaign was benefiting from the crossfire between Nutter and Knox, quietly deploying his organization.

"We're moving on a different path and hope to be in the front of this line on election day," Fattah said in an interview. "We feel extremely confident.

Ben Hayllar said the flyers were distributed at his parish, St. Katherine's of Siena in Torresdale, after the 10 a.m. Mass. He called it a "slimy" tactic.

He is a Nutter supporter but that is not why he was offended, Hayllar said. "It suggests Catholics are bigots, for one thing, and doing it at the last minute makes it very hard to respond," said Hayllar, who was finance director in the Rendell administration.

Judy Hartl discovered the flyers on cars parked near St. Mary's Catholic Church in Society Hill as she walked along Locust Street toward Washington Square. "The campaign has been not so nasty until recently, and I felt good about that," Hartl said. "We have a number of good candidates. This annoyed me." She said it was particularly offensive for someone to impugn the reasons Nutter changed churches.

To view slide shows on each of the candidates, along with their profiles, campaign promises and more, visit http://go.philly.com/mayor. Go to philly.com tomorrow for updated coverage of the primary.EndText

Contact staff writer Marcia Gelbart at 215-854-2338 or mgelbart@phillynews.com.