Who is Robert Mueller? Former FBI director, Trump foe dies at 81.

Former FBI director Robert Mueller, who served as special counsel in an investigation into Russia's interference during the 2016 presidential election, died on March 21 at age 81, leaving behind a decorated legacy and notable foes.

Mueller — who was diagnosed with Parkinson's disease in 2021, according to the New York Times — died on Saturday, his family confirmed in a statement obtained by USA TODAY.

"With deep sadness, we are sharing the news that Bob passed away last night," Mueller's family said in the statement. The family didn't specify the cause of death, but asked for their privacy to be respected.

Mueller leaves behind his wife of nearly 60 years, Ann Cabell Standish, two daughters and five grandchildren.

He earned the enmity of President Donald Trump by serving as special counsel investigating Russia's interference in the 2016 presidential election. Trump said on social media: "I’m glad he’s dead."

Here is what to know about Robert Mueller.

Who was Robert Mueller?

Born on Aug. 7, 1944, in New York City, Mueller grew up outside of Philadelphia before graduating from Princeton University in 1966 and later earning a master's degree in International Relations at New York University, according to his bio on the FBI's website.

Following college, Mueller joined the U.S. Marine Corps, where he served as an officer for three years, leading a rifle platoon in Vietnam. For his service, Mueller received a Bronze Star, two Navy Commendation Medals, the Purple Heart (given to those wounded or killed in action) and the Vietnamese Cross of Gallantry, his bio says.

After Mueller's military service, he earned a law degree from the University of Virginia Law School in 1973. Mueller would then work as a litigator in San Francisco until 1976, before serving 12 years in U.S. Attorney’s Offices, first in the Northern District of California in San Francisco and then in Boston as an Assistant U.S. Attorney.

Mueller would go back and forth between Boston-based law firms and U.S. Attorney's Offices until 1998, when he was named U.S. Attorney in San Francisco. He held this position until 2001, when former President George W. Bush and the Senate unanimously confirmed him to become the sixth director of the FBI on Sept. 4, 2001. He took office just one week before 9/11, remaining in the role until his 12-year term ended on Sept. 4, 2013.

Robert Mueller led Russia collusion investigation

Appointed as special counsel on May 17, 2017, by Deputy Attorney General Rod Rosenstein, Mueller was tasked to "oversee the previously-confirmed FBI investigation of Russian government efforts to influence the 2016 presidential election and related matters," according to a Justice Department news release.

The investigation came to a head when Mueller gave his final report in 2019, which concluded that Russia had interfered in the 2016 election to help then-presidential candidate Trump. However, there was no evidence that anyone associated with Trump's campaign at the time colluded with the Russian government.

Trump would call the investigation a hoax on several accusations. He also blamed former President Barack Obama's staff.

What was Robert Mueller's cause of death?

A statement from Mueller's family didn't specify the cause of death, but asked for their privacy to be respected.

Mueller's death comes nearly five years after being diagnosed with Parkinson's disease. He learned of his diagnosis in the summer of 2021, the New York Times reported, citing a 2025 family statement the outlet obtained, which came days before he had been called to testify before a congressional committee about the government's handling of the Jeffrey Epstein sex trafficking investigations. 

According to the Cleveland Clinic, Parkinson's disease is an age-related degenerative brain condition that causes parts of the brain to deteriorate, causing slowed movements, tremors and balance issues.

Contributing: Aysha Bagchi, USA TODAY

(This story has been updated to add new information.)