Fred Karger has described the National Organization for Marriage (NOM) as “a crooked organization.”

Karger, the president of the gay rights group Rights Equal Rights, made his remarks before reporters in Des Moines, Iowa, where he filed an ethics complaint against the group.

“They're a crooked organization,” he said. “They defy the law willingly.”

Karger's complaint charges that NOM, the nation's most vociferous opponent of gay marriage, failed to disclose donors behind two campaigns aimed at ousting four Iowa Supreme Court justices who joined the court's unanimous 2009 ruling which struck down the state's laws limiting marriage to heterosexual couples. Three justices were removed from the bench in 2010, but an attempt to unseat a fourth justice in 2012 failed.

“I think it's important that if people are going to participate in the process, they need to abide by state and federal laws. And this National Organization for Marriage does not agree with that position,” Karger added.

On Thursday, Karger will travel to Washington, D.C. to file a second complaint against NOM with the Federal Election Commission.

(Related: Rick Santorum, gay marriage foe NOM accused of paying for conservative endorsement.)