No one talks about Jackson occupying the mayor’s office anymore, and the predictions that he might someday run for president — forecasts that accompanied his arrival in Congress 16 years ago — are long forgotten. Instead, Jackson’s promising career has devolved into a blur of self-destruction, mystery and tabloid drama. He’s been caught in an extramarital affair and been pulled into the pay-for-play scandal that toppled Rod Blagojevich as Illinois governor and prompted a House ethics investigation. He’s disappeared without explanation from Congress, only to surface while receiving treatment for depression and, as first reported by the Chicago Sun-Times and confirmed with law enforcement sources Monday, he is under federal criminal investigation for allegedly misusing campaign funds to decorate his Washington home.

Jackson’s family did not respond to repeated requests for comment, and numerous Jackson allies also declined to be interviewed.

Jackson hasn’t appeared in public since June 8, even though he’s up for reelection next month. On that day, the congressman — who had served as national co-chairman for Barack Obama’s 2008 presidential campaign — announced a plan to increase the minimum wage and accused the president of failing to live up to a campaign promise to lift the wage. It was classic Jesse Jr. — sharp, articulate and utterly quixotic. Few gave him a chance of passing the bill that he announced with Rep. Dennis Kucinich (D-Ohio) and liberal crusader Ralph Nader by his side.

Then Junior was gone.

Shifting stories

Scraps of information surfaced — fragments of the story, a drip-drip-drip that frustrated rather than sated. More than two weeks after his final public appearance, Jackson’s staff said he’d gone on leave June 10 because of “exhaustion.” Capitol Hill staffers were growing frustrated because they couldn’t get any information about Jackson. House Minority Leader Nancy Pelosi (D-Calif.) and Minority Whip Steny H. Hoyer (D-Md.) urged Jackson to reveal more about what was happening. Two weeks after that first announcement, there was another clipped statement — this time a “mood disorder” was cited — and his staff tried to shoot down an NBC report that he was receiving treatment for alcohol abuse.

Another two weeks passed, and now the Mayo Clinic was saying he was being treated for “depression and gastrointestinal issues.” And in mid-August, Mayo announced that Jackson had been diagnosed with bipolar II disorder. The statement noted that he had undergone weight-loss surgery in 2004, a procedure the clinic said could lead to difficulty absorbing minerals and medicines.

“The information we’ve been given has been sparse,” said Rich Hofeld, a staunch Jackson ally who is mayor of the Village of Homewood, a Chicago suburb. “I think people kind of raise their eyebrows and question what is going on.”