Complex sentence: Two days later, on a Sunday morning, Rankin witnessed a vigilante mob lynch Perkins from the rafters of the Piper stage, while the mob also pulled out their guns and shot Perkins' dangling body.
Split into simpler sentences: Two days later, on a Sunday morning, Rankin witnessed the lynching of Perkins at the hands of a vigilante mob who hung Perkins from the rafters of the Piper stage. The mob also pulled out their guns and shot Perkins' dangling body.