Complex sentence: Erickson reveals that he knows of Strahm's death, and moment Hoffman's voice is unscrambled, he kills everyone in the room, plants fingerprints from Strahm's severed hand, and then sets the room on fire to destroy the evidence.
Split into simpler sentences: Erickson reveals that he knows of Strahm's death, and Hoffman's voice is unscrambled. Hoffman kills everyone in the room, plants fingerprints from Strahm's severed hand, and then sets the room on fire to destroy the evidence.