DENVER (CBSNewYork/AP) — The Southern Poverty Law Center wants to add two gun rights groups to its lawsuit on behalf a gay New Jersey couple, who said their image was used in a political mailer in Colorado.

The SPLC said in court documents Wednesday that Rocky Mountain Gun Owners and the National Association for Gun Rights joined with what the organization deemed an “anti-gay hate group” called Public Advocate of the United States to attack candidates running in the 2012 Colorado Republican primaries.

The SPLC sought to add the two gun rights groups, as Dudley Brown, who serves in executive positions for both groups, and Lucius O’Dell and Andrew Brown, employees of the National Association for Gun Rights. The SPLC alleged the two groups conspired with Public Advocate of the United States to create mailers featuring an image of Brian Edwards and Thomas Privitere of New Jersey without their permission or that of the photographer who took the picture.

The mailer showed Edwards and Privitere’s engagement photo, but replaced the New York City skyline snowy and rural backgrounds that suggested a Colorado landscape, the SPLC alleged.

In one of the mailers, the words “State Senator Jean White’s idea of ‘Family Values?’” appeared in boldface red letters in over Edwards and Privitere’s photo, the SPLC said.

Dudley Brown proposed the mailers in an e-mail to Public Advocate of the United States a year ago, saying “[t]he gay lobby smells blood in the water, and if some pro-gay legislators don’t lose their primaries, I fear Colorado will tumble [and pass legislation authorizing civil unions] in the 2013 session,” the SPLC said in a news release.

“It’s shocking that so many groups worked together to defile a photo that meant so much to me,” Privitere said in the release. “I am sickened by this discovery and the depths these groups are willing to sink to attack the gay community. It’s obvious they don’t care who they hurt, just as long as they get their propaganda out.”

The lawsuit, filed in U.S. District Court in Colorado, claimed the groups stole the couple’s image, and infringed on photographer Kristina Hill’s exclusive right to the copyrighted photo, the SPLC said.

The original lawsuit named Public Advocate of the United States as a defendant.

The gun groups didn’t return calls seeking comment from The Associated Press.

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