Complex sentence: Mynter, who participated in the autopsy, later stated his belief that the bullet lodged somewhere in the back muscles, though this is uncertain as it was never found: after four hours, Ida McKinley demanded that the autopsy end.
Split into simpler sentences: Mynter, who participated in the autopsy, later stated his belief that the bullet lodged somewhere in the back muscles, though this is uncertain as it was never found. After four hours, Ida McKinley demanded that the autopsy end.