How the NYTimes Found the Pentagon Leak Suspect

From an Inside the Times column by Mark Scheffler headlined “Finding the Pentagon Leak Suspect”:

The murky digital trail started with four items posted to Russian channels on the messaging app Telegram, each consisting of a photograph of a classified U.S. intelligence report. Aric Toler, a freelance reporter who works with us, noticed that several similar documents had also been posted elsewhere and figured that the original source of the leaks had to be somewhere other than Telegram. But he couldn’t find it.

“I looked and looked,” Aric said.