Alabama Senate candidate Roy Moore is facing legal trouble after it was revealed he failed to disclose a $540,000 promissory note from his charity to the Internal Revenue Service when he filed his candidacy.

Now, the Campaign Legal Center is asking for an investigation into the Alabama Republican, according to a filed complaint obtained by the Washington Examiner.

According to the documents provided in the complaint, Moore reportedly worked part-time at the foundation which he founded. Between 2007 and 2012, he racked up a total of $540,000 in back pay compensation, which he failed to disclose on his amended Senate Financial Disclosure Report.

"The purpose of the financial disclosure report is to give voters and the public basic information about the sources and nature of a Senate candidate's income and assets," the CLC noted in their complaint.

The complaint explained that the lofty promissory note was necessary for Moore to file separately because it "is a distinct asset from the mortgage that backs it." For example, the value of the foundation's building could fluctuate in the housing market but the promissory note guarantees him money.

"Failing to disclose a $540,000 promissory note for deferred compensation for part-time work for a charity deprives voters of the information necessary to hold candidates and officials accountable," they explained.

It's unclear whether Moore paid taxes on the money. He and his campaign did not return requests for comment from the Washington Post, which first reported the story.

The CLC sent their complaint to the Senate Select Committee on Ethics hoping for an investigation into his candidacy, arguing that Moore's actions violated Senate rules and deceived voters.

Moore, who already faced pushback on discrepancies on his financial disclosure forms, defeated Sen. Luther Strange in last month's GOP runoff to fill the seat vacated by Attorney General Jeff Sessions.