The federal investigation into alleged Russian agent Mariia Butina stemmed from a series of suspicious, high-dollar money transfers to limited liability companies tied to Butina and her onetime boyfriend, South Dakota-based GOP operative Paul Erickson, according to a new report.

The Tuesday report by McClatchy laid out the origins of the probe into possible Russian attempts to infiltrate and channel money to the National Rifle Association. According to McClatchy, the NRA probe predates President Trump’s January 2017 inauguration, and is being overseen by the U.S. attorney’s office for the District of Columbia, rather than Special Counsel Robert Mueller.

Butina was charged in July with conspiracy against the United States and serving as an unregistered agent for Russia who worked to infiltrate the NRA, among other conservative groups. She pleaded not guilty and is in a Washington, D.C. jail awaiting trial. Erickson has not been charged, but is believed to be the individual described in court documents as “U.S. Person 1” who helped Butina coordinate her activities.

Republican operative Paul Erickson also was involved in the financial dealings that drew investigators’ interest – transfers of money exceeding $10,000 to limited liability corporations, including two created in Erickson’s home state of South Dakota, the sources said. Both of these people, including one of the sources and a third individual, also spoke on condition of anonymity because of the confidential nature of the investigation.

Per McClatchy, the interest of investigators at the Treasury Department was first piqued after they received a number of Suspicious Activity Reports related to LLCs linked to the couple, including some funds transfers that “appear to have come from Russia.”

At a July 18 court hearing, both federal prosecutors and Butina’s lawyer, Robert Driscoll, suggested that there was a federal fraud investigation ongoing into Erickson in South Dakota. Both parties said Butina offered to assist in that probe.

Driscoll confirmed to McClatchy that some $20,000 passed through Bridges LLC, one of the South Dakota entities that the couple incorporated in 2016. The money consisted of four $5,000 payments that Butina received from the Outdoor Channel for consulting work on a segment about bear hunting in Russia, according to Driscoll.