A Republican U.S. Senate candidate has stirred controversy for calling the country's largest Muslim rights group a "terrorist" organization, but he is in company with a prominent Muslim Arab Gulf state.

And his claim is backed by FBI evidence presented at a terrorism funding trial in which the group, the Council on American-Islamic Relations, was named by the Justice Department an unindicted co-conspirator.

Further, an undercover investigation that obtained original documents and recorded conversations of CAIR leaders provided solid evidence the Washington, D.C.-based group is a front for the Muslim Brotherhood and its Palestinian branch, Hamas.

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The congressional candidate, Josh Mandel, who is Ohio treasurer, sent a Twitter message Wednesday declaring CAIR "is Hamas" and posted an article about the Palestinian faction that controls the Gaza Strip, reported the website Terror-Alert.com, which describes itself as an informational project of New York-based WorldAlert LLC.

The caption read: "If Council on American Islamic Relations is for it, it is probably bad for America. What a horrible organization."

A day later, he said on Twitter that CAIR also had ties to the Muslim Brotherhood.

If you support WND’s fight to expose CAIR and the Muslim Brotherhood, please consider a donation to the WND Legal Defense Fund for court fights like this one – which must be one if America is to remain free – and safe.

Terror-alert.com stated that while "many have accused CAIR of being a front for such disparate groups as Hezbollah and Hamas - armed groups in the Middle East with vastly different ideologies - no firm proof has ever been produced to support these claims."

But CAIR has been unable to refute evidence in court.

For example, when CAIR filed a lawsuit in 2009 against an undercover investigative team that published evidence of CAIR's ties to the Muslim Brotherhood, Hamas and Islamic jihad, the group alleged its reputation was harmed, and it sought damages in court.

But a federal court in Washington determined CAIR failed to present a single fact showing it had been harmed, and the organization gave up that specific claim against former federal investigator Dave Gaubatz and his son, Chris Gaubatz, whose findings were published in a WND Books expose, "Muslim Mafia: Inside the Secret Underworld That's Conspiring to Islamize America," which will be released in a paperback edition in a little more than a week.

Get the new paperback edition of "Muslim Mafia."

The Muslim Arab Gulf state United Arab Emirates has designated CAIR as a terrorist organization along with groups such as ISIS and al-Qaida.

In 2008, the FBI cut off official contact with CAIR, citing evidence from the Holy Land Foundation trial in Texas that documented the connections between CAIR and Hamas.

CAIR's parent organization, according to FBI wiretap evidence from the Holy Land Foundation case, was founded at an October 1993 meeting of Hamas leaders and activists in Philadelphia that included CAIR Executive Director Nihad Awad. The organization, according to the evidence, was born out of a need to give a "media twinkle" to the Muslim leaders' agenda of supporting violent jihad abroad while slowly institutionalizing Islamic law in the U.S.

Yet, the executive director of CAIR's Ohio office, Julia Shearson, told Al Jazeera her organization has spent years dispelling "rumors" about its ties to foreign groups.

She said the Senate candidate, Mandel, "wants to have a higher office than he has now, and he's going to use the ladder of Muslim hate to get there."

"Unfortunately, it is a popular tool these days."

While CAIR has complained of the unindicted co-conspirator designation, as WND reported in 2010 a federal judge later determined that the Justice Department provided “ample evidence,” affirming the Muslim group has been involved in “a conspiracy to support Hamas."

In the case against the WND Books authors, the U.S. District Court in Washington observed in May 2014 that CAIR had been "frustratingly unclear as to the injuries at issue for each of the claims." The court found CAIR speaks "in broad generalizations, asserting injuries and damages and proximate cause across multiple counts and multiple Plaintiffs."

In addition, CAIR leaders have made statements affirming the aim of establishing Islamic rule in the United States.

The Islamic organization long had accused WND and others of "smearing" the Muslim group by citing a newspaper account of CAIR founder Omar Ahmad telling Muslims in Northern California in 1998 that they were in America not to assimilate but to help assert Islam's rule over the country.

But WND caught CAIR falsely claiming that it had contacted the paper and had "sought a retraction," insisting Ahmad never made the statement.

In a telephone conversation with WND in 2003, CAIR's communications director, Ibrahim Hooper, insisted someone from CAIR’s California affiliate made the contact with the paper.

When confronted with the fact that the newspaper’s editors had told WND that CAIR had not contacted them and that the reporter stood by the story, Hooper abruptly ended the call, saying: “If you are going to use distortions, I can’t stop you; it’s a free country. Have a nice day.”

Minutes later, however, Hooper called back and said he wanted to change his statement to say, “We will seek a retraction, and we have spoken to the reporter about it in the past.”

But three years later, the issue arose again, and WND found CAIR still had not contacted the paper.

Hooper, himself, also has expressed a desire to overturn the U.S. system of government in favor of an Islamic state.

"I wouldn't want to create the impression that I wouldn't like the government of the United States to be Islamic sometime in the future," Hooper said in a 1993 interview with the Minneapolis Star Tribune. "But I'm not going to do anything violent to promote that. I'm going to do it through education."

If you support WND’s fight to expose CAIR and the Muslim Brotherhood, please consider a donation to the WND Legal Defense Fund for court fights like this one – which must be one if America is to remain free – and safe.