Robert Mueller, reportedly dubbed as the ‘no-nonsense’ former FBI chief, who became special counsel in charge of investigating ties between Russia and Donald Trump's presidential campaign for 2016 elections, passed away on Saturday. He was 81-years-old.

He was also a decorated Vietnam War veteran who led the FBI in the aftermath of the September 11, 2001 attacks on the US.

In 2025, a report by the The New York Times mentioned that Mueller had been diagnosed with Parkinson's disease.

On Saturday, his death was reported by MS NOW and a New York Times journalist who posted a statement attributed to the Mueller family.

Robert Mueller cause of death No cause of death for Mueller was mentioned, reported Reuters.

FBI chief who stayed over at Obama's request Robert Mueller was the second-longest-serving director the history of FBI – only J. Edgar Hoover. Mueller held the job until 2013 after agreeing to former US President Barack Obama’s request to stay on even after his 10-year term was up, mentioned a report by AP.

He retired in 2013, but was summoned back to public service by a senior Justice Department official four years later as a special counsel to take over an inquiry into Russia's election meddling after Trump fired then-FBI chief James Comey.

Probe into Russia-Trump campaign ties Robert Mueller’s Russia investigation – released in 2019, detailed what he and US intelligence agencies described as a coordinated Russian campaign involving hacking and propaganda.

The effort, they said, was aimed at sowing division in the US, undermining Democratic candidate Hillary Clinton, and supporting Donald Trump, seen as Moscow’s preferred candidate, mentioned Reuters' report.

Russia, however, has denied any interference in the election campaign.

"First, our investigation found that the Russian government interfered in our election in sweeping and systematic fashion," Mueller had said during 2019 congressional testimony.

"Second, the investigation did not establish that members of the Trump campaign conspired with the Russian government in its election interference activities. 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 added.