The North Carolina NAACP has asked the state to investigate illegal robo-calls and whether they were intended to suppress voter participation, particularly among blacks.

The NAACP filed a formal complaint May 2 with the N.C. Attorney General and the State Board of Elections against Women’s Voices Women Vote, a Washington, D.C., nonprofit behind the robo-calls, that sowed confusion in the weeks leading up to the primary.

“We believe that the state attorney general and the Board of Elections needed to do a much more aggressive investigation,” said Al McSurely, lawyer for the state NAACP. “It wasn’t just stopping them. It was whether there was an intentional effort to stop minority voters.” At press time, McSurely said state officials have not yet responded to the complaint.

On April 24 and 25, thousands of potential voters received an automated call from a black man, who identified himself as Lamont Williams and told listeners they would receive voter registration packets in the mail. Williams told the call recipients to sign and return the registration packets to “be able to vote and make your voice heard.” Others received a call from an unidentified woman who delivered a similar message. The calls confused many people because they had already registered to vote and the state deadline to mail in registration cards for the primary had already passed. Also, the call did not mention that North Carolinians could easily register to vote in the primary through the state’s same-day registration and early voting program.

Following the concerns about the calls, which were first reported on the Institute for Southern Studies’ blog Facing South, Women’s Voices Women Vote issued a press release stating that the calls were never intended to register voters for the primary, but for the November general election. Still, N.C. Attorney General Roy Cooper said the calls are illegal and ordered Women’s Voices Women Votes to stop making them (state law requires automated calls to name the organization that paid for the call). The State Board of Elections also denounced the calls.

The NAACP complaint asks state officials to examine the Women’s Voices Women Vote mailing list to determine whether the calls from Lamont Williams targeted blacks, whether call recipients were registered, and which misleading message people received. Democracy N.C., a voter rights organization, is also a party to the complaint.

According to Facing South, Women’s Voices Women Vote has initiated similar calls in at least 11 other states, earning the condemnation of election officials over the questionable tactics. The N.C. NAACP is considered filing an all-encompassing complaint with the U.S. Department of Justice.