(CNN) The Justice Department inspector general's office has made inquiries into how the department handled the changing sentencing recommendations of Roger Stone, according to two sources.
The IG initially took interest in the case after the four prosecutors on it resigned in protest of Attorney General William Barr's intervention. Stone was eventually sentenced to 40 months in prison and President Donald Trump later commuted the sentence altogether.
"We welcome the review," Justice Department spokeswoman Kerri Kupec said on Monday.
A spokesperson for the IG's office would not confirm or deny the investigation.
NBC News first reported the inquiry on Monday.
It's unclear what impact any investigation by Inspector General Michael Horowitz may have on the Justice Department or on the current state of politics -- with the President repeatedly praising Stone and attacking investigators as part of his reelection campaign. The independent watchdog's purview is relatively limited to fact-finding and making recommendations, and reports from the IG's office often take months if not years to produce.
Career prosecutors with the Justice Department in Washington originally recommended a harsh sentence for Stone's convictions of lying to Congress, obstruction and threatening a witness. But Barr stepped in, toning down what the Justice Department requested for his penalty after the President criticized the recommendation in a tweet.
The four prosecutors on the case resigned before the sentencing, and since then, two have publicly said -- in a Washington Post column and in testimony to Congress -- they believed Barr was undercutting the law to protect a friend of the President's.
The incident has long drawn scrutiny about Barr's political influence over cases of interest to the President. The prosecutors at Stone's trial proved their case that Stone had lied to Congress about his attempts to contact WikiLeaks in 2016 in order to protect the President.
Since then, the Justice Department and Senate Intelligence Committee have made public investigators' findings that Trump may have known of Stone's efforts and that the campaign encouraged Stone's pursuit of stolen emails that could help Trump win the 2016 election.