After President Trump fired FBI Director James Comey in May 2017 but before the appointment of Special Counsel Robert Mueller, then-acting FBI Director Andrew McCabe opened an obstruction of justice investigation, two people with knowledge of the matter told CNN on Thursday.

McCabe and Deputy Attorney General Rod Rosenstein were both concerned about President Trump's behavior, CNN reports, and they discussed several different ways they could rein him in, including having Rosenstein wear a wire while meeting with him (when The New York Times first reported this detail in September, Rosenstein denied it). CNN says the FBI had been considering launching the investigation even before Comey was fired, because of Trump asking Comey during an Oval Office meeting to end the investigation into former National Security Adviser Michael Flynn.


A Department of Justice official told CNN Rosenstein never attempted to curtail Trump, but others with knowledge of the matter said Rosenstein and several top FBI officials did worry about Trump's behavior. For more on the chaotic days after Comey's firing, visit CNN. Catherine Garcia