According to The New York Times, citing sources, US federal prosecutors are now investigating secret Turkish lobbying work that involved Flynn. Mueller, who is leading an investigation into alleged Russian interference in the 2016 US presidential campaign — allegations that Moscow has repeatedly and categorically denied — was also in charge of probing the Turkey case, but eventually sent it back to the prosecutors in Virginia who had originally opened the investigation.
In a memorandum filed with the court earlier this week, Mueller's office recommended that Flynn be given no prison time for lying to the authorities about his ties with Turkey, given his substantial assistance in the Russia probe.
Last December, Flynn pleaded guilty for lying to the FBI about his contacts with then-Russian Ambassador to the United States Sergey Kislyak during the transition period when President Donald Trump assumed power. Flynn also admitted that he misinformed Vice President Mike Pence about his communication with the Russian ambassador and decided to resign from his post in February 2017.
The investigation into the Turkey case started in 2016, after Flynn published an article in The Hill newspaper accusing Fethullah Gulen — a cleric residing in the United States, who Ankara believes masterminded the failed coup in 2016 — of being radical Islamist. Investigators regard this article as part of a bigger lobbying scheme, where Flynn discussed with senior Turkish officials in December 2016 a possible deal under which the former would be paid to organize Gulen's return to Turkey.