Washington (CNN) UPDATE: Late Friday night, Attorney General Jeff Sessions announced that he had fired former FBI Deputy Director Andrew McCabe less than two days shy of his retirement. McCabe had been expected to retire this Sunday, on his 50th birthday, when he would have become eligible to receive early retirement benefits.

Original story: Andrew McCabe, the former No. 2 at the FBI who is fighting for his job in the wake of an internal investigation just hours ahead of his official retirement, potentially stands to lose out on hundreds of thousands of dollars in retirement benefits if the Trump administration decides to fire him before the week is out.

McCabe joined the bureau in New York in 1996 and rose through the ranks, ultimately becoming the deputy to then-FBI director James Comey in early 2016 and overseeing some of the most high-stakes investigations in the agency.

Along the way, he's drawn the ire of President Donald Trump, whose top spokesman called McCabe a "bad actor" on Thursday, as well as the scrutiny of the Justice Department's inspector general for his involvement in the bureau's probes of Hillary Clinton.

On his 50th birthday -- this Sunday -- the veteran law enforcement official would become eligible for early retirement benefits, given his 20-plus years of service, according to federal guidelines.

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