The FBI and IRS have launched an criminal investigation into the Republican Party of Florida's issuing of credit cards to elected officials and staff, according to media reports.

The probe could affect the tumultuous Florida Republican Senate primary. An IRS inquiry is probing the tax returns of campaign front-runner Marco Rubio, former state party chairman Jim Greer, a close ally of Rubio's opponent Gov. Charlie Crist and another state GOP official.

The statements are being examined to see if the men used party credit cards improperly for personal use.

Former Florida House Speaker Ray Sansom is said to be the original target of the probe, which is being investigated separately. He allegedly included $6 million in the state budget for an airline hangar for a friend of a campaign donor.

Greer resigned in January after coming under pressure for overspending.

Rubio's campaign has denied that the candidate engaged in wrongdoing.

Here is more from the St. Petersburg Times:

Rubio campaign adviser Todd Harris said Tuesday that the former lawmaker from Miami has not been contacted by any federal investigators.

 "There is absolutely nothing to this,'' he said. "Anyone who is looking into it or investigating will quickly come to the same conclusion.''

At this stage of the IRS investigation, agents are looking at federal tax records, state financial disclosure forms and other documents to see whether Rubio, Greer and Johnson may have personally benefited from using their GOP American Express cards without reporting or paying taxes on additional income.

"They would be interested in pursuing a case if the amount of money was big and it was being spent on people and things that were prohibited under the GOP's structure,'' said Jose I. Marrero, former special agent in charge of the IRS's South Florida office.

The party stopped issuing credit cards last year after Greer cut up his own American Express card at a party meeting to try to quash the uproar over spending.

Rubio billed the party for more than $100,000 during the two years he served as House speaker, according to credit card statements obtained by the St. Petersburg Times and Miami Herald. The charges included repairs to the family minivan, grocery bills, plane tickets for his wife and purchases from retailers ranging from a wine store near his home to Apple's online store. Rubio also charged the party for dozens of meals during the annual lawmaking session in Tallahassee, even though he received taxpayer subsidies for his meals.

Rubio said the billings all related to party business — the minivan, for example, was damaged by a valet at a political function — and that he repaid the party for about $16,000 in personal expenses.

Asked during his campaign bus tour last week if he needed to amend his tax returns to reflect any party money that covered his personal expenses, Rubio said, "We don't believe it's income. It's not. . . . Whatever the law is, we're going to comply, but I don't think it's income.''

Greer, who was forced to resign in January amid allegations that he misspent party money, said of the IRS inquiry, "I paid all my taxes and did everything my accountant told me to do.''

Cross-posted to the Ballot Box