Former FBI director Robert Mueller has died, according to reports on Saturday.

Mueller was appointed special counsel for the Russia 2016 election interference investigation that took place during the first Trump administration.

Mueller, 81, had investigated whether the 2016 Trump campaign colluded with Russia. 

Trump reacted to the death on Truth Social.

"Robert Mueller just died. Good, I’m glad he’s dead. He can no longer hurt innocent people!" he wrote.

Mueller's final report on the Russia probe was released in 2019, which was the third year of Trump's four-year first term.