Special counsel Robert Mueller says charging a president with a crime was “not an option” his team could consider in the Russia investigation.

Mueller says that he was bound by longstanding Justice Department opinions that say a president can’t be indicted while in office.

In his first public comments in the probe, Mueller said on Wednesday “it would be unfair” to potentially accuse someone of a crime when the person couldn’t stand trial to defend himself.

Mueller’s comments echoed the findings in his public report.

Mueller’s report revealed that President Donald Trump tried to seize control of the Russia probe and force Mueller’s removal to stop him from investigating potential obstruction of justice by the Republican president. Trump has called the investigation a “witch hunt.”

He also said he’s leaving the Justice Department now that he’s concluded his Russia investigation.

Mueller has been on the Justice Department’s payroll since he formally concluded his probe in March. Last month, Attorney General William Barr publicly released a redacted version of his Russia report.

It’s unclear what Mueller has been doing at the Justice Department since, though the Democrat-led House Judiciary Committee has been negotiating with his office in an attempt to secure his public testimony before Congress. So far, no deal has been made.