A newly-unsealed FBI filing reveals further evidence that a Civil War reenactor in Virginia made violent threats against his own organization and then pinned them on Antifa, a loose collection of left-leaning militant anti-fascist groups.

In 2017 and 2018, a series of anonymous threats were made against the nonprofit Cedar Creek Battlefield Foundation. The first threat came in the form of a pipe bomb, which was found unexploded on the grounds where the foundation holds its annual reenactment and led to its swift cancelation. The following year, the gathering was again canceled after someone sent several threatening letters to the foundation and its associates, promising to disrupt the reenactment with guns, explosives, poison, dog feces, and “cups of human urine.” The sender wrote the letters on fake Antifa “letterhead”—which doesn’t actually exist among the decentralized, independent factions—and mailed them in envelopes bearing phony Antifa logos.

The news of Antifa’s involvement initially caused outrage among the far-right.

But, as first reported by Quartz earlier this year, federal investigators believe the letters were in fact sent by Gerald Leonard Drake, a former volunteer at the Cedar Creek Battlefield Foundation who was upset about being kicked out of his Civil War reenactment unit after a 2014 dispute. Now, previously unknown details have surfaced in a 104-page search warrant application that further tie the 61-year-old registered sex offender to the bogus threats.

In exacting his alleged revenge, Drake apparently tried to inflame existing tensions between Antifa and members of the right-wing, which had repeatedly faced off, sometimes violently, at protests around the country at the time, most notably in nearby Charlottesville just a few months before the threats were sent.

The first of the threat letters, postmarked Sept. 21, 2017, was was addressed to the “Cedar Creek Battlefield Event People,” in Middletown, VA. Others were mailed from Maryland and Pennsylvania.

“As the nine threat letters were postmarked in three different states,” the latest filing says, the FBI believes “the writer intended to mail the letters in varying geographical locations in order to increase the difficulty in identifying the writer.”

It didn’t work. According to the document, investigators compared the locations of the mailboxes from which the threat letters were mailed with location data from Drake’s cell phone. The results, the FBI says, place Drake in the vicinity of each specific mailbox at the time the letters were sent.

Credit card purchases Drake made nearby offer additional proof that he was in the area during the relevant periods.

To top things off, Google location data shows Drake’s phone was mere yards away from where the pipe bomb at the 2017 reenactment was discovered, at the precise time it was found.

Quartz was unable to reach Drake for comment. He does not have a lawyer listed in court records.