Senate Minority Leader Chuck Schumer, D-N.Y., on Tuesday called for an Inspector General investigation into the Department of Justice’s decision to reduce the recommended prison sentence for President Trump’s former adviser Roger Stone.

Four career DOJ prosecutors who recommended Stone serve seven to nine years in prison for lying to Congress, obstruction and witness tampering, resigned from their posts earlier Tuesday following the announcement.

DOJ PROSECUTORS RESIGN AFTER TOP BRASS REVERSES COURSE ON ROGER STONE SENTENCING

In the letter sent to Inspector General Michael Horowitz, Schumer wrote, “This situation has all the indicia of improper political interference in a criminal prosecution.”

He asked Horowitz to investigate on what basis the recommendations were withdrawn, who made the decision at DOJ and who was involved at the White House.

He added that the American people’s confidence in impartial justice can’t be sustained if “the president or his political appointees are permitted to interfere in prosecution and sentencing recommendations in order to protect their friends and associates."

Schumer told reporters, "The president seems to think the entire Justice Department is just his personal lawsuit to prosecute his enemies and help his friends. Rule of law in this grand tradition in this wonderful Justice Department is just being totally perverted to Donald Trump's own personal desires and needs and it's a disgrace.”

Fox News reported earlier Tuesday that top brass at the DOJ were "shocked" that prosecutors handling the case had recommended Monday night that Judge Amy Berman Jackson sentence 67-year-old Stone to between 87 and 108 months in prison.

The prosecutors asserted in the Monday filing that Stone's conduct post-indictment -- including violating the judge's social media gag orders -- merited a sentence much longer than the 15 to 21 months that the defense said was actually advisable under the federal sentencing guidelines.

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In a new, amended filing Tuesday afternoon, the DOJ told Jackson that the government "respectfully submits that a sentence of incarceration far less than 87 to 108 months’ imprisonment would be reasonable under the circumstances," but that the government "ultimately defers to the Court as to the specific sentence to be imposed."

Fox News' Gregg Re, Jake Gibson and David Spunt contributed to this report.