Attorney General Eric HolderEric Himpton HolderHouse easily passes prison reform bill backed by Trump On Trump and DOJ, both liberals and conservatives are missing the point Holder: DOJ, FBI should reject Trump's requests MORE’s chief of staff, who was targeted by Republican lawmakers in their probe of Operation Fast and Furious, will be leaving the Justice Department.

A DOJ official on Monday, though, said top aide Gary Grindler’s departure was part of the normal turnover between terms, according to a report from Fox News

Holder praised Grindler in a statement, saying he had “demonstrated time and again his good judgment and an ability to make the tough — and correct — decisions."

“Throughout his tenure — as acting deputy attorney general and as my chief of staff — Gary has played a central role in our work to protect the American people and I will always be grateful for his dedication to the department, his service to our nation and his sound advice and personal friendship,” said Holder. 

Grindler had served in the post since January 2011 and had been a target of GOP criticism in Republicans' investigation of a botched DOJ gun-tracking program.

Holder’s statement thanking Grindler and announcing his departure did not mention the Fast and Furious operation.

The mishandled program has been the focus of GOP congressional probes, with Republican lawmakers questioning when Holder and his top officials first learned about the program.

One of the weapons used by the DOJ in the operation, which sought to connect Mexican drug cartels to straw purchasers, was found at the murder scene of U.S. Border Patrol Agent Brian Terry.

Grindler was cited in a report from House Oversight Committee Chairman Darrell Issa (R-Calif.) which criticized Justice officials’ oversight of the controversial operation.

Issa hailed his departure and said that he expected other officials tied to Fast and Furious to step down. Issa called Grindler’s exit “warranted and long overdue.” 

In his report on the DOJ operation, Issa said Grindler was first made aware of the program in March 2010, and should have taken steps to stop the operation or notify Holder about its tactics, but did not.

A separate DOJ inspector general probe also concluded that Grindler and other top officials knew enough about the operation to have alerted his superiors and raised concerns about the mission sooner.

Those officials “failed to alert the attorney general to significant information about or flaws in those investigations,” that report concluded. The inspector general recommended disciplinary action for those officials.

GOP lawmakers are continuing their investigation into the operation, with the Oversight Committee pursuing a lawsuit in federal court to compel Holder to turn over additional documents. 

President Obama, though, has asserted executive privilege over many of those requested documents.

Democrats say that Issa is conducting a politically motivated probe and has wasted taxpayer dollars. 

The Justice Department has turned over 7,600 pages in response to congressional inquiries, but Holder is resisting additional subpoenas, which he says could hamper ongoing criminal investigations.

Holder requested the inspector general's investigation into the department’s handling of Fast and Furious, but Republicans have questioned the independence of that probe.

This story was last updated on Dec. 5th at 10:38 a.m.