WASHINGTON -- More details have emerged about Republican Indiana Senate challenger Richard Mourdock taking campaign donations from people who may have business with the state.

The Huffington Post reported last week on Mourdock, who is the state treasurer, soliciting bidders to run a $50 million fund for the Indiana State Police Pension at the same time he was holding a fundraiser with finance companies. If any of the people solicited for the fund-raiser were interested in bidding, it could be a violation of Securities Exchange Commission rules against "pay-to-play" arrangements.

Mourdock did not release the bidding companies, but his campaign called the news a fabrication of the campaign of incumbent Sen. Dick Lugar (R). The latest poll showed Mourdock leading Lugar by 10 percentage points going into Tuesday's primary.

Now a local radio show host, Gary Snyder, has posted several apparent instances of people who have state business donating to Mourdock. In one case, the CEO of College Savings Bank, Gilbert Johnson, donated $500 to Mourdock a couple weeks after his company started offering certificates of deposit in the state's 529 college savings plan. Mourdock was quoted in the press release.

In another instance, the head of Home Bank, Dan Moore, donated repeatedly to Mourdoch. His bank participates in the same savings program.

Like with the original report, Mourdock's campaign denied even the appearance of wrong-doing.

"This is a completely baseless last minute attempt by the Lugar campaign to sling yet more mud at Richard Mourdock," said campaign spokesman Chris Conor. "Just because someone files a complaint with the SEC does not mean there is an investigation," he added, referring the the original report in which a retired police sergeant wrote to the Securities Exchange Commission seeking a probe of Mourdock.

What's more, Conor argued: "The College Choice 529 CD Program is just that, a certificate of deposit at a bank. It is not a security. Therefore, the SEC doesn't even regulate this product and has no jurisdiction to investigate this frivolous complaint. The complaint has zero merit."

He also noted that the larger state 529 plan is managed by Upromise. "The CD portion of the plan is a tiny fraction of the overall assets in the 529 Plan," Conor said.

Democrats -- who think they have a better chance running against Mourdock than Lugar -- have certainly noticed the stories, and would like answers, as well.

"Accusations of pay-to-play in the Treasurer's office are a very serious matter," said Ben Ray, a spokesman for the Indiana Democratic Party, signaling the controversy is not likely die after the primary. "Stewards of taxpayer money have a responsibility to avoid even the hint of corruption. Richard Mourdock's conduct has been reckless."

Michael McAuliff covers politics and Congress for The Huffington Post. Talk to him on Facebook.