The DOJ just gave the clearest sign yet that Mueller is homing in on Comey's firingGet the Full StoryAlex Wong Getty ImagesThe Department of Justice won't allow the Senate Judiciary Committee to interview two top FBI officials, Carl Ghattas and James Rybicki, about the circumstances surrounding former FBI Director James Comey's dismissal in May, according to a letter obtained by CNN.
The DOJ cited "the appointment of Robert S. Mueller to serve" as special counsel in charge of the Russia investigation in a letter declining the committee's requests for transcribed interviews with Ghattas and Rybicki.
"Under these circumstances and consistent with the Department's long-standing policy regarding the confidentiality and sensitivity of information relating to pending matters, the Department cannot make Mr. Ghattas nor Mr. Rybicki available for transcribed interviews at this time," the letter read.
Ghattas is the executive assistant director of the FBI's national security branch and Rybicki is the FBI director's chief of staff and senior counselor.
That the DOJ cited Mueller and the Russia investigation when it declined the committee's requests to interview Ghattas and Rybicki indicated to legal experts that the FBI doesn't want its own probe of the circumstances surrounding Comey's firing to be compromised by Congress.
"It means that whatever the FBI officials would tell Congress is relevant to what Mueller is investigating," said former federal prosecutor Renato Mariotti. "It represents official confirmation that the firing of James Comey and the testimony of these two officials is part of the investigation."
Mueller is also examining a letter written by Trump outlining his reasons for firing Comey that was heavily edited, and ultimately blocked, by White House counsel Don McGahn.
Ty Cobb, the White House special counsel, disagreed with the characterization of the president's letter as potentially incriminating and called reporting to that effect "exaggerated and or fictionalized." But both McGahn and then-White House chief of staff Reince Priebus recently hired lawyers as the Russia investigation continues, and Mueller will likely interview them to determine whether Trump sought to obstruct justice and end the Russia investigation when he fired Comey.
Mueller's questioning, Mariotti said, "will be most effective if the witnesses know as little as possible about what other witnesses will say" — which would be harder if FBI officials gave an interview to Congress that would likely be leaked and or disclosed to Trump's defense team.
"The Congressional investigation serves an important function, because it can investigate conduct that is not charged as a crime," Mariotti said. "It can also reveal information to the public about important events of public concern for which there is a lack of evidence to charge. But those functions typically take a back seat to ensuring that an ongoing criminal investigation is not hindered in any way."NOW WATCH: Why you won't find a garbage can near the 9 11 memorial
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