From the National Park Service:
On Monday, October 3rd, an RV located at the park’s South Entrance burned severely before firefighters were able to extinguish the flames. Subsequent investigation revealed the bodies of three persons inside the vehicle. The bodies appear to be those of an adult and two children. An investigation into the identities and cause of death of the three is currently underway and is being conducted by the National Park Service with support from the Flagstaff Fire Department, the Coconino County Medical Examiner’s Office, the Federal Bureau of Investigation’s Evidence Response Team, and the Bureau of Alcohol, Tobacco, Firearms and Explosives. Preliminary investigation suggests the possibility of a murder-suicide and does not suggest the involvement of an unknown party. It is important to note that these findings are preliminary and that the investigation is ongoing. No identities will be made public until they have been confirmed and next of kin have been notified.