Deputy Attorney General Rod Rosenstein, who has overseen the lengthy criminal investigation into Russian meddling in the 2016 U.S. presidential election, is planning to leave the job when a new attorney general takes office.
President Donald Trump has often assailed Rosenstein for naming a special counsel, former FBI Director Robert Mueller, to lead the investigation into allegations the Trump campaign colluded with Russia to influence the outcome of the election.
The probe is also looking into whether Trump obstructed justice by trying to derail investigation. The president has called it a "witch hunt" and denies any collusion. Russia also denies any involvement.
Despite his attacks on Rosenstein, Trump refrained from firing him, even after he posted an image of Rosenstein and others behind bars.
Trump also fired former Attorney General Jeff Sessions for removing himself from oversight of the Russia probe, leaving it to Rosenstein.
WATCH: Rosenstein's Departure Raises Concerns About Russia Investigation
Rosenstein was apparently not fired but decided to leave on his own. He has reportedly told White House officials he will leave when the Senate confirms, as it is expected to, Trump's choice for the new attorney general, William Barr.
A career prosecutor, Rosenstein had apparently long thought that two years in the demanding job as the No. 2 official at the Justice Department was long enough to serve.
Former Justice Department official Hans von Spakovsky is downplaying the significance of Rosenstein's departure.
"He's moving toward the far end of the time most political appointees stay in office. I think at the end of two years, he's very ready to leave," von Spakovsky told VOA.
Rosenstein had signaled to other officials that he would leave when he was satisfied that Mueller's investigation was either complete or far enough long that it would be protected from White House interference.
Rosenstein played a key early role in Trump's May 2017 firing of James Comey, who as FBI director headed the Russia probe before Rosenstein named Mueller to take over. Rosenstein wrote a letter supporting the dismissal of Comey that the White House initially used as justification for Trump ousting him.
Within days, however, Trump told NBC News he fired Comey because he was thinking of "this Russia thing," contending that claims of Trump campaign collusion with Russia were a hoax perpetrated by Democrats dismayed by Trump's election win over Democrat Hillary Clinton.
Mueller has no set timetable for concluding his investigation and a grand jury hearing evidence in the case was extended for another six months, leaving some Washington analysts to conclude the probe was not close to being finished.
Despite Trump's complaints about Mueller, the special counsel has won convictions or secured guilty pleas for various offenses from several key figures in Trump's orbit: his former campaign chairman, Paul Manafort; his first national security adviser, Michael Flynn; former campaign aide Rick Gates; foreign policy adviser George Papadopoulos, and Trump's personal attorney, Michael Cohen, among others.
The confirmation hearing for Barr, who also was attorney general in the early 1990s, is set to start Tuesday, with a final Senate confirmation vote possible in mid-February.