“They were asking me if I was an infiltrator,” Horne told The Intercept. “My response was absolutely not.”

There was a lot Horne says he didn’t know at the time — for one, that Reznicek and Montoya had recently been involved in a series of acts of pipeline sabotage. Between March and May 2017, above-ground valves along the Dakota Access pipeline in Iowa and South Dakota were pierced with welding torches, creating new costs for the pipeline company, Energy Transfer, and sending its security personnel into a frenzy. A few weeks after their conversation with Horne, the two women would claim responsibility for the sabotage.

Another thing Horne says he didn’t know: that someone he considered a “brother in the cause” was indeed an infiltrator. For months, a man calling himself Joel Edwards had posed as a pipeline opponent, attending protests, befriending water protectors, and paying for hotel rooms, supplies, and booze. He told some people he had a job with a hotel that allowed him to travel, others that he was a freelance journalist reporting on the pipeline resistance. But five former contractors for TigerSwan, the secretive security firm hired by Energy Transfer to guard the pipeline, confirmed to The Intercept that Joel was an undercover intelligence operative. His real name was Joel Edward McCollough, and he had been sent to collect information on the protesters, explicitly targeting those who were down on their luck. Horne, who struggled with addiction, appeared to be a perfect target.