Members of special counsel Robert Mueller’s team are investigating an alleged meeting former national security adviser Mike Flynn attended with Rep. Dana Rohrabacher, R-Calif., in September 2016, according to a report.

Flynn’s company, Flynn Intel Group, arranged the Sept. 20 meeting in Washington, D.C., according to NBC News. Flynn, his son, Michael Flynn Jr., and his business partners, Bijan Kian and Brian McCauley, all attended the gathering.

Rohrabacher has pushed for improved relations between Russia and the U.S., and in May, House Majority Leader Kevin McCarthy, R-Calif., joked in a private phone call, “There’s two people I think Putin pays: Rohrabacher and Trump,” according to the Washington Post.

Mueller, who is investigating Russian meddling in the 2016 election, and his investigators are examining emails Rohrabacher’s staff received from Flynn Intel Group and interviewing witnesses. In the emails, Flynn Intel Group reportedly thanked Rohrabacher’s staff for the meeting.

It’s unknown whether Flynn and the California Republican discussed relations between the U.S. and Russia.

As part of his Russia probe, Mueller is investigating Flynn’s foreign contacts as well as his work for foreign governments, including Russia and Turkey.

Flynn Intel Group received $530,000 for work it did on behalf of the Turkish government while the 2016 campaign was going on. Flynn initially did not disclose the work, but he retroactively registered as a foreign agent with the Justice Department in March.

The former national security adviser also received $45,000 from RT, a Kremlin-backed news organization, to attend a gala in Moscow in 2015.

Flynn left his post at the White House in February after it was discovered he lied to Vice President Mike Pence about his contacts with then-Russian ambassador Sergei Kislyak.