Cummings targeted the organization, called True the Vote, saying the group planned to deploy hundreds of thousands of personnel to challenge the status of citizens who they believe may be ineligible to vote.

“There have been reports from multiple states during the past two years that your organization is targeting predominantly minority communities and coordinating with the Republican Party in an attempt to intimidate legitimate voters,” Cummings wrote in his letter to Catherine Engelbrecht, True the Vote’s president and founder.

Cummings first contacted the group in early October seeking specifics of its plans. In his most recent letter, he set a deadline of Oct. 31 for the group to turn over its plans.

The congressman pointed to a recent report documenting True the Vote’s plans to deploy personnel to predominantly African-American and Hispanic communities in North Carolina. Following the report’s release, Cummings said True the Vote shut down access to its Web site which detailed where its workers will be located on Election Day.

Cummings also said the group had been connected to voter suppression allegations in Texas in 2010. According to Cummings, officials in Harris County, Texas told his staff that “King Street Patriots and True the Vote volunteers were not fully exonerated for acts of intimidation while serving as poll watchers in 2010,” saying that True the Vote members were the subject of complaints from voters who said the members stood too close while the citizens voted.

Cumming said “mounting evidence” shows the group is coordinating with Republican political interests to further that party’s agenda.

Cummings wrote in the letter: “If you are truly committed to transparency in our nation’s voting process—and if you continue to deny that your organization is challenging thousands of legitimate voters across the country for partisan political purposes—then you should have no reason to withhold documents from Congress about your activities.”