Complex sentence: He tells Alex that he killed Cavalierre to toy with Alex and will also kill his grandmother and his children, and that JOHN SAMPSON, Cross' best friend and partner, who was watching over NANA MAMA, DAMON and JANELLE, cannot stop him.
Split into simpler sentences: He tells Alex that he killed Cavalierre to toy with Alex. He's going to kill his grandmother and his children, and JOHN SAMPSON, Cross' best friend and partner, who was watching over NANA MAMA, DAMON and JANELLE, cannot stop him.