Cold Case Murders; Citing this act as "The Decker Act"; requiring the heads of law enforcement agencies or their designees to review certain cold cases and make a specified determination upon receiving a written application from a designated person; requiring law enforcement agencies to conduct a full reinvestigation of a cold case under certain circumstances; requiring law enforcement agencies to provide specified training; requiring law enforcement agencies, by a specified date and periodically thereafter, to report certain data to the Global Forensic and Justice Center at Florida International University, etc.