Complex sentence: Goren and Eames initially suspect that someone connected with the organized crime had the couple killed, since they were in a witness protection program, but the detectives soon realize the victims' surviving daughter goes missing while searching for her biological parents.
Split into simpler sentences: Goren and Eames initially suspect that someone connected with organized crime had the couple killed, since they were in a witness protection program. However the detectives soon discover that the victims' surviving daughter goes missing in the process of searching for her biological parents.