A former city councilman who promised to tackle corruption and a surging murder rate won Tuesday's Democratic mayoral primary over a big-spending business executive and two popular congressmen.

Michael Nutter, 49, emerged from a five-man field after surging in the final weeks of the campaign. He spent months attacking two-term incumbent John Street, who is barred by term limits from running again.

Nutter, who gave up his council seat to run for mayor, had 35 percent of the vote with 82 percent of precincts reporting. Businessman Tom Knox had 27 percent, followed by U.S. Reps. Bob Brady and Chaka Fattah.

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Nutter is expected to be the overwhelming favorite in November. Nearly four of five city voters are Democrats. The city has not elected a Republican mayor in nearly 60 years. Business leader Al Taubenberger was unopposed in the Republican primary.

A wild card could be a possible third run for office by former Republican Sam Katz, who has not ruled out seeking the mayor's office as an independent in the general election. Katz lost twice to Street.

Knox's self-financed campaign got off to a fast start because of heavy advertising, but appeared to have slowed as Nutter's campaign took off.

The Knox campaign got a scare Tuesday afternoon when police said two men wearing "Knox for Mayor" shirts pulled out a gun and robbed a campaign office in North Philadelphia. The men fled on foot with an unknown amount of campaign cash.

Brady is a longtime behind-the-scenes political power broker in Philadelphia. Fattah is in his seventh term in Congress. State Rep. Dwight Evans has struggled to attract much voter support.

Voters have consistently called crime the most important issue in a city with more than 400 homicides last year, the most in nearly a decade. Slayings in 2007 are on pace to break last year's total.

The candidates offered a variety of anti-crime plans, including proposals for hiring hundreds more police officers. Nutter pushed one of the most controversial ideas — a police "stop-and-frisk" program in the most violent neighborhoods.

The candidates also spoke about the need to clean up City Hall in the wake of a corruption probe that became public when an FBI bug was found in Street's office a month before the 2003 election. Street was never charged, but the probe netted the convictions of nearly two dozen people, many with close ties to the mayor.

The racial makeup of the crowded field further muddied the electoral picture in a city with nearly equal numbers of black and white voters. Evans, Nutter and Fattah are black; Knox and Brady are white.

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