'What's taking so long to expose crooks?'

That headline isn't mine. It's from a column the Detroit Free Press published earlier this month. Clevelanders, impatient for our public corruption investigation to show results, might be interested to know Detroit's getting antsy too.

You've heard about Kwame Kilpatrick, right? The lying, sexting, cop-firing, justice-obstructing former Detroit mayor? Scandal and a tough local prosecutor knocked Kilpatrick (pictured, in mug shot) out of office a year and a half ago. Now, a massive FBI probe of Detroit City Hall -- which has already brought down the former city council president -- seems to be aiming to add bribery charges to Kilpatrick's tawdry legacy.

The feds seem late to the party, so columnist Rochelle Riley called up the U.S. Attorney in Detroit and asked, what's the hold-up?

"There are important investigative reasons that it can take so long," Barbara McQuade told Riley. "Sometimes, you have to work your way up a chain," she said. "Sometimes, you talk to someone who pleads guilty and that leads you to new people. And we're analyzing records that lead to other records."

That's how federal investigators in Cleveland are pursuing Jimmy Dimora and Frank Russo: Still not charging them with a crime, still racking up guilty pleas from potential witnesses 21 months after raiding county offices.

They're getting results. Consider Bruce Zaccagnini, one of the lawyers who's pleaded guilty to bribing Russo with $1.2 million in cash kickbacks. From the Plain Dealer story on his February sentencing:

As soon as federal investigators approached Zaccagnini, he agreed to help make their case against his co-conspirators. The financial records he handed over revealed the corruption was more extensive than investigators had realized, Assistant U.S. Attorney Antoinette Bacon said at the sentencing. "He saved months upon months of agents' time," Bacon said.

Could "more extensive" mean $1.2 million?

The water-torture drip of charges have triggered wild mood swings in the town and the targets themselves. Dimora's gone from reclusive to obnoxiously defiant to subdued to cocky again. He swung back to his innocent-persecuted self-defense last month, because he thinks some of the latest charges against buddies of his are weak -- they did work on his house but didn't do county work.

The favors Dimora allegedly did for the latest contractors may seem small -- recommendation letters and such. But the prosecutors are trying to establish a pattern they can take to trial. The explosive charges involving Steve Pumper look more damning if other contractor buddies testify that they, too, helped remake Dimora's back yard into a patio paradise and didn't get paid until the FBI started nosing around.

Clevelanders want charges, trials, verdicts, closure. But as impatient as they feel now, many of them would be furious if Dimora walked -- if jurors in a future trial were to decide that the investigation had left some fuzzy gray areas between Dimora's Vegas trip and barbecue shelter and his alleged nudges and phone calls at the county building.

In the meantime, the town could use some reassurance from the normally tight-lipped local U.S. attorneys, something like the words McQuade, a Detroit native, offered Riley:

"We recognize the need to act with thoroughness, but also a little bit of urgency," she said. "The city really needs some closure, and it's not healthy for anyone in this city to have a cloud of suspicion hanging over them indefinitely. In public corruption cases, we want to move as quickly as we can."