Three people who worked for Ron Paul's presidential campaign in 2012 were charged Wednesday with conspiring to buy the support of a former Iowa state senator.

An indictment unsealed Wednesday charges Jesse Benton, John Tate and Dimitrios Kesari with conspiracy and several other related crimes.

The indictment says the three former Ron Paul staffers negotiated with former Iowa State Sen. Kent Sorenson to switch his support in the 2012 race from Minnesota Rep. Michele Bachmann to Ron Paul in exchange for money.

"Federal campaign finance laws are intended to ensure the integrity and transparency of the federal election process," said Assistant Attorney General Caldwell in a statement. "When political operatives make under-the-table payments to buy an elected official's political support, it undermines public confidence in our entire political system."

Benton, a political operative with deep ties to the Paul family, now is a lead strategist for a super PAC supporting the 2016 presidential candidacy of Paul's son, Kentucky Sen. Rand Paul, and is married to Ron Paul's granddaughter.

Benton and Tate have lead roles at the super PAC supporting Rand Paul's 2016 campaign, America's Liberty.

A spokesman for Rand Paul's 2016 said in a statement to Fox News late Wednesday that Paul was “disappointed” the Justice Department chose to unseal the indictment prior of the first Republican presidential debate on Thursday.

“It certainly appears suspiciously timed and possibly, politically motivated.  Additionally, these actions are from 2012 and have nothing to do with our campaign,” the spokesperson added.

In a statement to Fox News, Benton’s lawyer Roscoe Howard said his client has cooperated with the government over the course of the investigation.

“That this indictment is now suddenly announced on the eve of the first Republican Presidential debate strongly supports our belief that this is a politically motivated prosecution designed to serve a political agenda, not to achieve justice,“ Howard said.

The indictment says Benton, Tate and Kesari negotiated a payment of $73,000 to Sorenson, concealing the payments in campaign records and filings. The indictment also says the arrangement was concealed from Ron Paul himself and that Benton initiated the deal.

Ron Paul said in a statement Wednesday that he was “extremely disappointed” on the government’s decision to prosecute the case.

“I think the timing of this indictment is highly suspicious given the fact that the first primary debate is tomorrow,” he said.

The Iowa state senator involved in the case pleaded guilty last year to charges stemming from the switch of support from one Republican candidate for president to another.

Sorenson admitted to receiving thousands of dollars in "under the table payments" from a 2012 presidential campaign and lying about the money, the Justice Department said at the time. Iowa state Senate rules forbid any sitting lawmaker from being paid by a campaign while in office.

The Associated Press contributed to this report.