Updated 05/23/12 - 9:44 p.m.
CHICAGO (CBS) -- U.S. Attorney Patrick Fitzgerald announced Wednesday that he will be stepping down at the end of next month.
Fitzgerald will step down on June 30 after almost 11 years in office. He took over on Sept. 1, 2001, making him the longest-serving U.S. Attorney for the Northern District of Illinois.
Fitzgerald's nomination by then-U.S. Sen. Peter Fitzgerald was considered a full frontal assault on corruption in Chicago.
Patrick Fitzgerald became a national celebrity for going after political corruption in Illinois. Most notably, he led the prosecutions of both Gov. George Ryan and Gov. Rod Blagojevich, who are both serving time in prison.
Though many observers thought former Mayor Richard M. Daley was Fitzgerald's ultimate target, Daley was never charged with any wrongdoing, and has since retired from office.
"I know Pat Fitzgerald, he doesn't have a bullseye on my back," Daley said while he was still mayor.
Fitzgerald's focus was not limited to politicians; the huge Operation Family Secrets case bagged well-known mob figures for murders that had gone unsolved for decades.
He also led the prosecutions of media mogul Conrad Black, and former police Cmdr. Jon Burge – who was convicted of lying about torturing suspects.
Fitzgerald also helped lead Project Safe Neighborhoods, an effort along with Chicago Police and the U.S. Bureau of Alcohol, Tobacco, Firearms and explosives and the Cook County State's Attorney's office to reduce gun violence.
As a special prosecutor, he also led the probe of the outing of CIA Officer Valerie Plame, which resulted in the conviction of Bush administration official Lewis Scooter Libby in 2007.
The Brooklyn, N.Y., native previously served in the U.S. Attorney's office in Manhattan, where he participated I the prosecution of Osama bin Laden for the 1998 bombings of U.S. embassies in Kenya and Tanzania, and of the suspects convicted of setting off a bomb at the World Trade Center in 1993.
Former federal prosecutor Patrick Cotter – who worked with Fitzgerald in New York, and has defended clients indicted under Fitzgerald in Chicago – said he's stunned by the news.
"I'm surprised. I think most lawyers in town will be surprised by this, because we felt he was in his dream job," Cotter said. "I never thought he would leave. I always thought he had the best job. In his view, he had the best job in the world. He seemed to be very happy at it. He was very good at it."
He also said Fitzgerald leaves a remarkable legacy.
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"Pat injected an even higher degree of zealousness – I would term it appropriate zealousness – but zealousness and energy into the office," he said.
Cook County Commissioner William Beavers, who was charged with tax evasion under Fitzgerald's watch, was among those who have accused Fitzgerald of abusing the enormous power of his office.
"This man is like a wild man on a train," Beavers said after pleading not guilty in March. "Somebody needs to stop him. He has caused three deaths – Michael Scott, Orlando Jones, and Chris Kelly -- with these Gestapo-type tactics that he used to try to make them tell on their friends."
Scott Fawell, who was Governor George Ryan's Chief of Staff, testified against his boss only after Fitzgerald turned the screws on his girlfriend.
CBS 2 Legal Analyst Irv Miller said that kind of tactic is not an abuse of power.
"It's not an abuse of power, it's an aggressive use of power. There's a difference. He is a pit bull when it comes to things like public corruption. That's his reputation, and he's not gonna let go," Miller said.
But when Fitzgerald went after Rod Blagojevich, he might have crossed the line, with comments he made when announcing the charges against the sitting governor, proclaiming in 2008 that Blagojevich had committed "conduct that would make President Lincoln roll over in his grave."
Even so, many defense attorneys who faced off against Fitzgerald's office had high praise for his skill as a prosecutor.
"I like Patrick, I really do. People don't believe me. I think he's a tremendous lawyer," defense attorney Thomas Durkin said. Durkin defended Robert Sorich, who ran Daley's patronage office and was convicted of rigging city hiring tests to favor politically-connected job applicants.
Though Durkin praised Fitzgerald's skill as an attorney, he also noted they didn't always see eye-to-eye on the cases that went through the federal courts.
"My world is a lot greyer than Patrick's world. I think he sees the world in a lot more black and white than I do," Durkin said.
Attorney Sam Adam Jr., who represented Blagojevich in the first trial against the former governor, had mixed reviews for Fitzgerald on his way out.
"I think sometimes that office had a culture and an attitude of win at all costs, and that's the question that I have, is it worth it?" Adam said. "With that said, you have to be honest about it. Was Chicago and the Northern District of Illinois better off with him? There's no question about it."
Blagojevich was convicted and sentenced to 14 years in prison last year, but in the ex-governor's first trial, Adam won a hung jury on all but one count.
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Adam says Fitzgerald did a good job going after corruption, but overdid it with deals for bad guys, such as political fundraiser Stuart Levine, who testified against fellow fundraiser Tony Rezko, and against Blagojevich.
"He ended up with a five-year sentence, and still to this day hasn't spent a day in jail," Adam told WBBM Newsradio's John Cody, "and in order to give him that, all he had to do was testify against Rezko – who was nowhere near as corrupt – and Blagojevich – who never took a dime, and everybody agrees never took a dime – and they end up with twice the amount of sentence and are in prison today."
Cotter said Fitzgerald has been apolitical when it comes to rooting out corruption.
"I don't honestly think there's a political bone in his body. He enforces the law as he sees it," Cotter said.
As for Fitzgerald's future career, Cotter said he could easily see him on the federal bench, or opting for private practice.
"I think that if he wants to go into private practice, I can, off the top of my head, name about 100 law firms in Chicago that would be thrilled to have him join them," Cotter said.
Last year, there were rumors that Fitzgerald might be appointed FBI director, but Robert Mueller remains in that position.
Even before he was elected, President Barack Obama was asked to promise to keep Fitzgerald, which he did, allowing him to leave on his own terms, which he will at the end of next month.
Odds are Fitzgerald's first assistant, Gary Shapiro, will take over at least temporarily, with no permanent replacement expected until well after the November election.
If re-elected, Obama would be free to name a Democrat for the post. If Republican Mitt Romney wins the election, he'd undoubtedly choose to continue the GOP's decade-long hold on the office.
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