The investigation and the loose ends

The sheriff's office publicly deflects attention from deputy Steven Calkins, but behind the scenes, they are investigating one of their own. The investigation grows as several agencies join the Collier County Sheriff's Office, including the Florida Department of Law Enforcement and the U.S. Attorney's Office. What did they do to search for evidence in the disappearances of Felipe Santos and Terrance Williams? What clues did they follow? Was the investigation thorough? Impartial? Was it too late?