Rep. Marsha Blackburn is locked in a competitive and expensive race for Senate. But the Tennessee Republican’s campaign decided to return a sizable contribution from a political action committee that’s facing scrutiny from campaign finance regulators.

“Club for Conservatives PAC did not meet our standards for transparency,” Blackburn campaign spokeswoman Abbi Sigler said.

Club for Conservatives burst on the scene in October when Brooke Pendley, a student at East Carolina University, started a PAC with help from her father and sent out numerous fundraising emails to boost Republican Roy Moore, who was running for Senate in Alabama.

The PAC was initially registered with the Federal Election Commission in Lexington, Kentucky, and has a mailbox in Charlottesville, Virginia, and an office for volunteers in Clemmons, North Carolina. There’s more background on Club for Conservatives here, here, and here.

Club for Conservatives contributed the maximum amount of $2,700 to Blackburn’s Senate campaign on Dec. 29. But the money was returned to the group on Jan. 4, according to the PAC’s first quarter FEC filing that detailed its financial information for the first three months of the year.