Former FBI Director Robert Mueller, who also served as special counsel investigating Russian interference in the 2016 election, has died. He was 81.

Mueller’s family reportedly confirmed the death in a statement to the New York Times and MSNOW, but did not say the cause of death. The New York Times reported last year that Mueller had been diagnosed with Parkinson’s disease.

President Trump, a longtime foe of Mueller’s who accused the then-special counsel of running a “rigged witch hunt” against him, seemed to celebrate the news of his death in a statement posted to social media on Saturday.

“Robert Mueller just died,” Trump posted on Truth Social. “Good, I’m glad he’s dead. He can no longer hurt innocent people!”

Mueller took over as FBI director just one week before the September 11, 2001, terrorist attacks at the appointment of President George W. Bush. He lead the bureau for twelve years, making his tenure the second-longest of any FBI director.

After his retirement from the bureau, he was tapped to take over the Russia investigation by the Justice Department’s then–No. 2 official, Rod Rosenstein, after Trump fired then–FBI chief James Comey.

That 22-month-long investigation ultimately produced indictments against 34 people, including several Trump associates: Trump’s former campaign chairman Paul Manafort, Trump’s adviser Roger Stone, and Trump’s former national security adviser Michael Flynn. Manafort was convicted in 2018 on eight charges of financial wrongdoing and pled guilty to two others, while Stone was convicted of seven counts of lying to Congress, obstruction, and witness tampering, and sentenced to more than three years in prison. Flynn pled guilty to lying to the FBI. Trump pardoned all three men.

However, the investigation failed to connect Trump with any Russian-involved election malfeasance.

“First, our investigation found that the Russian government interfered in our election in sweeping and systematic fashion,” Mueller said during 2019 congressional testimony about his 448-page report.

“Second, the investigation did not establish that members of the Trump ​campaign conspired with the Russian government in its election interference activities,” Mueller added “We did not address ‘collusion,’ which is not a legal term. Rather, we focused on whether the evidence was sufficient to charge any member of the campaign with taking part in a criminal conspiracy. It was not.”

Mueller was a Princeton University graduate who went on to earn his master’s degree at New York University before joining the U.S. Marine Corps. He served as an officer for three years and received honors including the Bronze Star and Purple Heart.

He later earned a law degree from the University of Virginia before becoming a federal prosecutor and ultimately the head of the Justice Department’s criminal division.