(Reuters) - Reuters reporter Joseph Menn exclusively revealed on Friday that Democratic presidential candidate Beto O’Rourke belonged to one of the best-known groups of computer hackers as a teenager.

Within minutes, his special report was the most popular story on Reuters.com here and was picked up by other news outlets. But the origin of the story goes back more than two years.

Members of the group, which calls itself Cult of the Dead Cow, protected O’Rourke’s secret for decades, reluctant to compromise the former Texas Congressman’s political career.

After more than a year of reporting, Menn persuaded O’Rourke to talk on the record. In an interview in late 2017, O’Rourke acknowledged that he was a member of the group, on the understanding that the information would not be made public until after his Senate race against Ted Cruz in November 2018.

In an interview with Reuters senior producer Jane Lee, Menn explains how he broke the story and got O’Rourke to open up about his hacking days.

“I decided to write a book about the Cult of the Dead Cow because they were the most interesting and influential hacking group in history. They illustrated a lot of the things that I think are fascinating about hacking and security work.

“While I was looking into the Cult of the Dead Cow, I found out that they had a member who was sitting in Congress. I didn’t know which one. But I knew that they had a member of Congress.

“And then I figured out which one it was. And the members of the group wouldn’t talk to me about who it was. They wouldn’t confirm that it was this person unless I promised that I wouldn’t write about it until after the November election. That’s because the member of Congress had decided to run for Senate. Beto O’Rourke is who it was.

“I met Beto O’Rourke. I said ‘I’m writing a book about Cult of the Dead Cow, I think it’s really interesting. I know you were in this group. This book is going to publish after November and your Senate race is over. And he said, ‘OK.’

“And he told me about his time in the Cult of the Dead Cow.”

Menn explains more about the story on Twitter @josephmenn twitter.com/josephmenn