(The Hill) Former special counsel Robert Mueller, who investigated ties between Russia and President Trump’s 2016 campaign, was diagnosed with Parkinson’s disease four years ago, his family told The New York Times on Sunday.

“Bob was diagnosed with Parkinson’s disease in the summer of 2021,” the statement to the Times read.

“He retired from the practice of law at the end of that year. He taught at his law school alma mater during the fall of both 2021 and 2022, and he retired at the end of 2022,” the statement continued. “His family asks that his privacy be respected.”

A congressional committee had sought testimony from Mueller in its probe of the late financier and convicted sex offender Jeffrey Epstein.

Mueller served as FBI director in 2008, when a 60-count draft indictment against Epstein was dropped in exchange for his guilty plea to two lesser state prostitution charges. The so-called non-prosecution agreement was widely criticized after Epstein’s 2019 indictment, which accused him of continuing to abuse underage girls after his short stint in a local prison a decade earlier.

The House Oversight Committee said it would subpoena Mueller to testify before the committee on Tuesday. The committee said late last week that it intends to withdraw its subpoena, citing health issues.

People familiar with Mueller’s condition told the Times that, in recent months, the former FBI director has had difficulty speaking and has experienced mobility issues.