Federal investigators have opened a second criminal probe of embattled Rep. David Rivera (R-Fla.), examining undisclosed payments from a Miami casino to a company he has ties to, according to the Miami Herald.

At issue: a $1 million consulting contract between a dog track and casino and a marketing company owned by Rivera's mother. The Herald reports that the IRS's involvement indicates that Rivera might have evaded paying taxes.

Rivera's campaign denied that there was a new investigation. "The Miami Herald story is a recycling of the same old, false, misleading, unattributed, and unsubstantiated reporting that has characterized their coverage thus far," the campaign sent out in a release. "Contrary to the Herald’s insinuation, Congressman Rivera has not been contacted by the FBI or IRS on any matter whatsoever."

This is just the latest bad news for the embattled congressman. This is not the first ethics charge he has faced — he is dealing with questions about changes he made to state legislative disclosure forms. He also was accused in 2002 of running a mail truck off the road because it contained fliers attacking his ethics.

Rivera was initially left off a big-ticket fundraiser held by the National Republican Congressional Committee, and there has been some buzz that he could face a primary challenger. Democratic state Rep. Luis Garcia also announced this week that he would run against the congressman.

This post was updated at 11:36am to include the Rivera campaign's response.