Former National Security Adviser John Bolton has raised the possibility that President Donald Trump obstructed justice when he promised the Turkish president that an investigation into a Turkish bank would soon stop. Bolton describes in his upcoming book, The Room Where It Happened, an interaction between Trump and Recep Tayyip Erdoğan where the U.S. commander-in-chief said the U.S. probe into Halkbank would end when “all the Obama people were gone” from the U.S. Attorney’s office in the Southern District of New York. Speaking with ABC News in an interview slated to air Sunday, Bolton said the exchange “did feel like obstruction of justice to me.”

He added, “And I thought to myself—and I'm a Department of Justice alumnus myself. I've never heard any president say anything like that. Ever.” Attorney General William Barr announced late Friday that the U.S. Attorney for the Southern District of New York, Geoffrey Berman, would resign. Berman, who spearheaded the Halkbank investigation, said he would not. On Saturday, Barr said Trump had fired Berman, but Trump said he was “not involved.” Bolton declined to testify in Trump’s impeachment trial, which concerned a similar interaction regarding Ukraine.