Complex sentence: A character named Aldo Krasker gets his hands on the mask which leads him to subconsciously embark on a murder spree, Lt. Kellaway joins the investigation so he can find the mask.
Split into simpler sentences: A character named Aldo Krasker gets his hands on the mask which leads him to subconsciously embark on a murder spree. Lieutenant Kellaway joins the investigation so he can find the mask.