Following the release of an ad showing him puffing on a cigarette, an adviser for Republican presidential candidate Herman Cain is facing some extra scrutiny -- and it isn't just about his nicotine habit.

An Associated Press report released Friday found that Cain chief of staff Mark Block not only has a history of legal and financial problems, but is also haunted by several allegations of voter suppression.

Block entered politics in 1974 when he was elected to the Winnebago County Board of Supervisors at the age of 18. Twenty years later, in 1994, Block's record was blemished after he was accused of illegally coordinating the re-election campaign of state Supreme Court Justice Jon Wilcox with a special interest group.

Although Block agreed to pay $15,000 and was banned from Wisconsin politics for three years, he never admitted guilt and maintains that the charges were "ridiculous."

With his career in politics on hold, Block's personal life spun out of control. He took a job at Target, faced a foreclosure, a tax warrant from the Internal Revenue Service, a lawsuit over an unpaid bill and two drunken driving charges.

"That's why I don't drink anymore," he told the AP.

By 2005, things were looking up for Block after he was hired by the Koch Brothers-funded tea party group Americans for Prosperity (AFP). In his role as Wisconsin director of AFP, he met and bonded with Cain, who was serving as CEO of Godfather's Pizza at the time.

Then in 2007, Block found himself in the middle of another controversy when AFP launched a robo-call campaign against a proposed $119 million school building referendum. A Wisconsin prosecutor said the calls were misleading, but he declined to bring charges.

But it wasn't the last time Wisconsin's AFP chapter was accused of wrongdoing while Block was in charge.

The liberal group One Wisconsin Now revealed audio tapes last year that suggested the then-AFP director was involved in a "voter caging" scheme.

Voter caging is a tactic that attempts to invalidate voter registrations by sending non-forwardable mass mailings to certain groups of people like minorities and students. When the mail is returned, a "caging list" is created to officially challenge the registrations. Republicans have used the practice in small operations going back to 1958, but in 2004, more than half a million voters were targeted.

In the 2010 audio recording, tea party leader Tim Dake seemingly admitted that Block was in on a coordinated plot to suppress the votes of minorities in Wisconsin.

"So, what we're hoping is that the various groups in the coalition plus Americans for Prosperity and Mark Block, who has been in on this, and the Republican Party," Dake said, "[T]his is coming all the way from the top: Reince Priebus has said, 'We're in.' And there's a reason why these guys are volunteering to work with us. They have access to what they call Voter Vault, you know the records of voting. They can go in there and look for lapsed voters."

Block admitted to Milwaukee Journal Sentinel that his group sent about 500 letters to see if they were deliverable.

"About 10 letters were returned, which indicated to me there wasn't a problem," he said.

Cain told Fox News' Sean Hannity Thursday that he stands behind Block's unconventional methods.

"We have a saying in my campaign... let Herman be Herman," Cain explained. "Mark Block is my chief of staff and we also say let Mark be Mark."

Listen to this audio from One Wisconsin Now, uploaded Sept. 24, 2010.