Story highlights The Office of Congressional Ethics announced Tuesday that it's extending its investigation of Rep. Alan Grayson

Grayson is in a heated Democratic primary battle to seek retiring GOP Sen. Marco Rubio's seat

(CNN) An already nasty Senate Democratic primary fight for the seat of retiring Republican Sen. Marco Rubio got even more heated Tuesday with news that the House ethics committee is extending its probe of Rep. Alan Grayson.

The panel's announcement triggered the release of a report by the outside Office of Congressional Ethics, which outlined half a dozen allegations, including charges Grayson improperly managed a hedge fund while serving in Congress, used official staff for campaign purposes and failed to properly disclose business interests on annual financial forms.

The campaign of his Democratic primary opponent in the Senate race, Rep. Patrick Murphy, circulated the 74-page report shortly after its release.

The report, which was backed by all six members of the OCE, found that "there is substantial reason to believe that Representative Grayson improperly allowed the use of his name by four entities connected to Representative Grayson's hedge fund and Grayson Consulting, Inc. of Virginia, and received compensation through management fees from the Grayson Fund Management Company, LLC." It also found that through Grayson's retainer agreements in his law firms he may have held financial interests in legal proceedings involving the U.S. government while serving in the House, which would be in violation of the rules.

Grayson released a statement saying he welcomed the news that the committee didn't take the step of establishing a formal "investigative subcommittee" to dig into the OCE's allegations and blamed his "political opponents" for instigating the ethics review. He also noted that the report "does not identify any instance where the OCE actually found an ethics violation, or any violation of law."

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