AUSTIN — Tea party group Empower Texans sued Monday to block criminal investigations of an attack ad about Fort Worth Rep. Charlie Geren that it sent during primary season.

The Texas Tribune reported that Empower Texans filed a civil rights lawsuit Feb. 28 in federal court in Midland, seeking an injunction and a temporary restraining order on the district attorneys of Travis, Tarrant and Midland counties, as well as against Attorney General Ken Paxton. A hearing on the temporary restraining order is scheduled for Wednesday.

The lawsuit says that Empower Texans fears prosecution for using the name the "Texas Ethics Disclosure Board," which does not exist, and that the group plans to continue using it. Travis County District Attorney Margaret Moore told the Tribune that a criminal complaint against Empower Texans regarding the mailer is under review. The complaint from a Fort Worth-area voter claims the group broke a law that does not let people present themselves as government authorities.

The mailer sent by Empower Texans, operating under the name "Texas Ethics Disclosure Board," listed the lobbying clients of Mindy Ellmer, who is married to Geren.

"This notice from the Texas Ethics Disclosure Board is directed to voters in HOUSE DISTRICT 99 concerning a candidate for office who must disclose a relationship with a registered lobbyist pursuant to Tex. Gov't Code 572.0531," the mailer reads.

Geren, a Republican, told The Dallas Morning News in February that he'd countered Empower Texans' move by buying as many internet domain names for the group as possible.

He won his primary contest against Fort Worth businessman Bo French, who received thousands from Empower Texans and conservative backers that were trying to oust Geren and other moderate Republicans, many of whom were closely aligned with outgoing House Speaker Joe Straus.

In recent cycles, Empower Texans president Michael Quinn Sullivan has joined forces with social conservative groups such as Texas Right to Life, the Texas Home School Coalition and Texas Eagle Forum to try to defeat "RINOs" — deemed Republicans in name only.