He's activating the sleeper cells among the Black Bloc of Antifa. And also green lighting the Clown head shrinkers to unleash more of [their] MKUltrafied "mass shooter" assassin's.

That's just off the top of my head and just from reading the Twatter post. I'm sure there's some gematria based coded msg in here, too. Based on his use of capitalized words. Haven't had the time to really look at the "letter."