The Muslim American Society, on at least one country's list of terror organizations, paid for Minnesota Democratic Rep. Keith Ellison to take a pilgrimage to Mecca in 2008, The Washington Free Beacon reported.
Ellison, a practicing Muslim, is making a bid to become the next chairman of the Democratic National Committee.
The MAS was founded by the Muslim Brotherhood in 1993 to act as the "overt arm of the Muslim Brotherhood in the United States," the Free Beacon reported.
The House Ethics Committee questioned Ellison for failing to disclose the 16-day trip, which cost nearly $13,400, the Free Beacon notes, and Ellison ultimately was told he needed to disclose the trip as a gift.
The group has also contributed thousands to Ellison's congressional campaigns, the Free Beacon reported.
The MAS is on the United Arab Emirates list of terrorist organizations, and its radical roots is a fact of which Ellison should have been aware.
"The Muslim American Society had been identified as an arm of the Muslim Brotherhood, both in reputable news reports like the Chicago Tribune as well as by the federal government, by the time Rep. Keith Ellison made his decision to accept the 2008 trip," Kyle Shideler, director of the Center for Security Policy's Threat Information Office, told the Free Beacon.
"If we are to be charitable, at a minimum Ellison ought to have known the nature of the organization he was associating with, as even the most basic due diligence would have discovered it," Shideler said.
To this point, the biggest controversy to Ellison's bid for DNC chair is whether he takes on the job full-time, a mistake Democrats don't want to repeat after Debbie Wasserman-Schultz.