A Republican political operative committed suicide days after telling the Wall Street Journal he had worked with Russian hackers to acquire Hillary Clinton’s missing emails, it was revealed Thursday.

The Chicago Tribune reported that 81-year-old Peter W. Smith killed himself in a Minnesota hotel room in May by putting a bag over his head and filling it with helium. He left behind numerous documents, including an apparent suicide note in which he said he was in poor health and his life insurance was running out, the Tribune reported.

About 10 days before, Smith had granted an interview with the Journal, in which he detailed his efforts to uncover the 33,000 deleted Clinton emails in 2016. Smith told the Journal he had found several hacker groups, including two from Russia, who claimed to have access to the emails, but he was unable to confirm their authenticity.

In his hunt for the emails, Smith reportedly implied he was working with Michael Flynn, then a campaign adviser to Donald Trump, though he later told the Journal that Flynn was not involved. Flynn was forced out as national security adviser in February after being caught in a series of lies.

The cause of Smith’s death had previously been a mystery, though it was widely assumed he had died of natural causes. The hotel where his body was found is located near the Mayo Clinic in Rochester, Minn.

In a note, Smith said his death involved “NO FOUL PLAY WHATSOEVER” and that he was ending his life because of “RECENT BAD TURN IN HEALTH SINCE JANUARY, 2017” and “TO LIFE INSURANCE OF $5 MILLION EXPIRING,” the Tribune reported.

A medical examiner’s report listed the cause of death as “asphyxiation due to displacement of oxygen in confined space with helium.” A helium tank was reportedly found in his room.

Smith was a longtime Republican donor from Chicago, and for years financed opposition research against former President Bill Clinton.