Mayor John Street (search)'s re-election campaign seemed lackluster -- until his office was bugged by the FBI.

Voters on Tuesday were deciding whether to re-elect the 60-year-old Democrat, who has ridden a wave of public skepticism about a federal public corruption probe, or to replace him with the businessman he narrowly beat four years ago.

Federal authorities have refused to say what the probe is about, but for a month, voters have been treated to headlines about agents seizing files related to city contracts, raids on the offices of two Street supporters and the seizure of three handheld computers the mayor uses for e-mail.

Rather than doom Street's campaign, the news seemed to give it new life. He has climbed steadily in the polls since Oct. 7, when police discovered the listening devices during a routine security sweep at City Hall.

Democrats rallied, charging that the investigation was an attempt by the Bush administration to disrupt the election. Black leaders also alleged that the FBI (search) unfairly targeted Street, the city's second black mayor, because of his race.

Meanwhile, his opponent, Republican businessman Sam Katz (search), was trying to avoid his third defeat in three tries for the office.

Katz has campaigned on promises to stimulate economic growth by cutting the city's wage tax and end cronyism at City Hall, but his message has been drowned out on the campaign trail by the uproar over the bugging.

The race is a rematch of 1999, when Street beat Katz by fewer than 10,000 votes out of more than 430,000 cast. That fight was resolved on racial lines. All but a few of the city's black neighborhoods voted for Street, while nearly all of its white neighborhoods voted for Katz.

Street, accompanied by his wife Naomi, arrived around 7:45 a.m. at St. Malachy's Parish School in North Philadelphia and briefly spoke with elementary-school students before casting his vote.

"These campaigns are long, and they're hard," Street told reporters. "It's always nice when they come to an end. I think we've had a great campaign. It's been very different from anything I've ever been through."

Katz, who waited in line for about a half-hour to cast his ballot, said that running for mayor had fulfilled a lifelong dream.

"You find out about your character. You find out about your ability to think," Katz told KYW-AM outside the Lutheran Theological Seminary (search) in the city's Mount Airy section.

In an early polling-place scuffle, a medical school professor said a Street supporter slapped him on the cheek after he complained the man was posting a Street sign over a Katz sign on the University of Pennsylvania campus just after 7 a.m.

Dr. Frank Curnett got treatment at an emergency room for the laceration. The alleged assailant fled and no immediate arrests were made, police said.

"That's not usually part of voting where I come from," said Curnett, 46, a Las Vegas native.

One voter, Catherine Burton, 70, said Tuesday morning that she voted for Street and approved of his record as mayor.

"He's helped the neighborhoods," she said. "He's building homes for people who never had them, for the young people who never had homes of their own. That means something, that means everything."

Nina Pritzker-Cohen, 36, said outside a downtown polling place Tuesday that she had jumped party lines and voted for Katz.

"I think the city needs a change and don't think Mayor Street has done enough to engage my vote, and I'm a Democrat," said Pritzker-Cohen, an interior designer.

The two campaigns spent some of their final hours Monday night accusing each other of planning to sabotage the election.

Democratic National Committee chairman Terry McAuliffe held a news conference Monday to allege that the Katz campaign planned to intimidate blacks on Election Day.

Katz campaign officials -- who had crashed the Democrats' news conference -- then held their own, accusing Street supporters of tearing down Katz campaign signs and harassing black voters who support the Republican.

"Where was Terry McAuliffe ... when my daughter, my wife and my grandchild were intimidated when they attempted to speak on Sam's behalf in the black neighborhood?" said Katz campaign co-chairman Carl Singley, who is black.

"It offends me in the worst sort of way to see these people come here and tell you that this is about protecting the rights of African-American voters. It is about preserving the interest of a corrupt regime," he said.

Brian Tierney, co-chairman of the Katz campaign, said that "prominent Democrats" had told him to "watch out" because Street supporters were plotting to slice the tires of Katz campaign automobiles intended to drive voters to the polls.