One of the best-known peddlers of fake news during the 2016 election died suddenly this past September, and it wasn’t immediately certain why. Now we know.

Paul Horner, an infamous writer who claimed he’s the reason Donald Trump is in the White House, died in Phoenix on Sept. 18 of a drug overdose, according to the Maricopa County medical examiner, who found a mix of drugs in his system, including the synthetic opioid fentanyl, according to the Arizona Republic.

For years, Horner wrote intentional fake news under the guise of satire using various pseudonyms and on different websites. He and his associates are perhaps best known for the National Report — an authoritative-looking site that churned out viral hits with bogus claims, such as Pope Francis endorsing Bernie Sanders’ presidential campaign.

Horner had been active prior to 2016 and previously told VICE News that stories about President Obama auctioning off seized marijuana were attempts at satire. But facilitating Donald Trump’s election last year was his capstone achievement, he told the Washington Post.

About a month before Election Day, senior Trump campaign advisor Kellyanne Conway and Donald Trump’s son Eric Trump tweeted links to one of Horner’s fake articles that claiming left-wing Trump protesters had been paid $3,500 to demonstrate at Trump rallies.

“Right now I make like $10,000 a month from [Google] AdSense,” Horner said to the Post in November 2016. “My sites were picked up by Trump supporters all the time. I think Trump is in the White House because of me.”

Horner previously had a history of drug use and spent a few months in jail, according to the Arizona Republic. Arizona governor Doug Ducey in June declared a public health emergency in the state due to the ongoing opioid crisis, with over 3,200 reported opioid overdoses between June and October — 400 of which resulted in death.