Robert Mueller, the former director of the Federal Bureau of Investigation who led the investigation into Russia's interference in the 2016 United States presidential election, has died at the age of 81. His former law firm confirmed his death. He had previously been reported to be living with Parkinson's disease.

Mueller served as head of the Federal Bureau of Investigation for 12 years, including in the aftermath of the September 11 attacks. In 2017 he was appointed special counsel to oversee the investigation into Russian election interference and possible links to Donald Trump's campaign, following Trump's dismissal of the bureau's director.

The 22 month investigation resulted in charges against 34 individuals and several Russian entities, along with multiple guilty pleas and convictions. Mueller concluded there was insufficient evidence to charge Trump or his campaign with participating in a broader criminal conspiracy with Russia, though his report detailed what he described as sweeping and systematic interference by the Russian government.

After Mueller's death was announced, Trump reacted on social media, writing, 'Good, I'm glad he's dead. He can no longer hurt innocent people!'