There is another possibility another individual has brought up online. The possibility that the single pilot onboard became incapacitated due to health issues ( passed away) not related to pressurization. The passengers in the passenger cabin may not have realized what may have happened to the pilot prior to the fuel exhaustion. The F16 pilots have only reported the pilot slumped over, nothing said about any passengers. I have flown this type of Citation and the pressurization system is pretty simple and reliable. Also for those who have little experience with FMS systems the flight track shown on FlightAware is easily programmed prior to flight and the autopilot would have followed it quite easily. The 180 degree turn at CCC vor is normal ATC routing in the New York area. Until the voice recorder is recovered, if there is one, and analyzed, we may never get an answer as to why this happened. RIP to those lost, condolences to the families involved.