Seven Democratic senators have accepted donations for their 2018 campaigns from Democratic super-lobbyist Tony Podesta, FEC files show.

Special counsel Robert Mueller is reportedly probing the Podesta Group as part of his investigation into Russian influence operations within the United States. Tony Podesta, whose brother John was Hillary Clinton’s campaign chair in 2016, resigned from the group on Monday following increasing scrutiny into his group’s lobbying activities for foreign entities. (RELATED: Podesta Group Plays Key Role In Manafort Indictment)

Six Democratic senators that Podesta gave money to are up for re-election in 2018 in states that Trump won.

Podesta gave $2,000 to Indiana Sen. Joe Donnelly, $1,500 to Missouri Sen. Claire McCaskill, $1,000 to North Dakota Sen. Heidi Heitkamp, $1,000 to Wisconsin Sen. Tammy Baldwin, $1,000 to West Virginia Sen. Joe Manchin and $1,000 to Montana Sen. Jon Tester, according to FEC filings.

Podesta also gave money to California Sen. Dianne Feinstein, whose seat is considered safely Democratic but is facing a primary challenger, and gave the legal maximum of $33,900 to the Democratic Senatorial Campaign Committee.