Mayor James Hahn's (search) re-election bid has suffered — along with the image of honesty he worked hard to cultivate — amid accusations he let corruption and fraud flourish at City Hall.

County prosecutors have been investigating allegations that Hahn supporters shook down companies that wanted to do business with the city by tying public contracts to political contributions. Federal prosecutors have opened their own inquiry.

Hahn has not been implicated and denies knowledge of any potential wrongdoing, but the investigations touch whole segments of city government — from members of Hahn's inner circle to Los Angeles International Airport and the water and power department.

No city official has been charged, though several have resigned.

But with prosecutors issuing subpoenas for Hahn's office e-mails and summoning some of his aides before grand juries, the investigations have become a popular topic for his four main challengers in the March 8 primary.

"He's the pinata. The question is the whether the pinata will survive," said Bob Stern, president of the nonpartisan Center for Governmental Studies (search) in Santa Monica.

Critics have cast Hahn's administration as the most corrupt since a scandal-plagued mayor was recalled nearly 70 years ago, and some of his supporters have withdrawn their endorsements.

"It's more than a scandal. It's crippled his administration," said Councilman Bernard Parks (search), a former police chief whose ouster was backed by Hahn and who is one of the mayor candidates.

Hahn has been reminding voters of his reputation for personal integrity.

"There's no factual basis for any of these charges," said Hahn's campaign consultant Kam Kuwata. "It's always rhetoric and hot air."

However, more than a third of respondents to a Los Angeles Times poll said Hahn lacks the honesty and integrity to be mayor. The poll also found that none of the five candidates appears to have the majority support needed to avoid a May 17 runoff. The race is nonpartisan, and all five major candidates are Democrats.

The investigations accelerated following an audit by Los Angeles' public watchdog, the city controller, that said shoddy records and meddling by political appointees in screening airport contracts gave the appearance of conflicts of interest and abuse. Separate audits criticized the secretive process by which the harbor department awarded leases and accused a publicity firm of overcharging the city's water and power agency by millions of dollars.

Local and federal prosecutors largely have refused to comment, though some details have surfaced:

— The federal probe yielded its only indictment last month, against a former executive at a public relations firm that had millions of dollars in contracts with City Hall. The executive pleaded not guilty to 11 counts of wire fraud in an alleged scheme to overbill the Department of Water and Power by $250,000. City Controller Laura Chick (search) said Hahn was using the firm's contract with the agency to burnish his own image.

— In December 2003, Chick announced she had given law enforcement agencies evidence of "potential illegal acts" uncovered during an audit of contracts at the airports department. She singled out the department's practice of letting politically appointed city commissioners review and recommend millions of dollars worth of contracts they later voted on.

Airport Commission President and Hahn fund-raiser Theodore Stein resigned following reports that he suggested an engineering firm might lose future contracts because it wouldn't donate $100,000 to the mayor's 2002 campaign against San Fernando Valley secession. Stein said the accusations were "unfounded" and "malicious."

Deputy Mayor Troy Edwards (search), previously finance chairman for the mayor's 2001 campaign, has resigned. Hahn said his departure was unrelated to the probes, but Edwards has testified before a county grand jury looking into contracts.

— In cases not connected to the contract probes, a prominent lawyer was charged last May with reimbursing contributors to Hahn's 2001 campaign, and a real estate developer was fined $270,000 by a city ethics panel that found he laundered campaign donations to Hahn and others.

"It does damage the city's reputation," Xandra Kayden, senior fellow at the University of California, Los Angeles, School of Public Affairs, said of the charges of corruption. "This isn't Tammany Hall (search) corruption, but it's a major loss of credibility."