SAGLE — The federal investigation into a deadly plane crash in the Cabinet Mountains in 2015 remains in a holding pattern.

Thursday marked the one-year anniversary of the National Transportation Safety Board’s release of a preliminary report into the Oct. 8, 2015, crash that presumably killed businesswoman and aviator Dr. Pam Riddle Bird. Two passengers in Bird’s Cessna 182P were confirmed fatalities in the crash on Round Top Mountain near Hope.

The report stated that Bird’s Cessna collided with large trees near a mountain ridge line and was destroyed by a post-crash fire.

Bird departed from the Bird Aviation Museum near Lake Pend Oreille and was initially bound for Minot, N.D., according to the NTSB. Stops in Maine and Florida were also planned.

The U.S. Air Force Coordination Center in Florida reported at 8:23 a.m. that it received emissions from an emergency locater transmitter northeast of Hope. A helicopter spotted the wreckage, NTSB’s report said.

The remains of Bird remain unaccounted for, according to Bonner County Coroner Kit Rose. The remains of passengers have been positively identified as Bessie “Tookie” Hensley and Don Hensley, 80 and 84, respectively. They were close friends and flying companions of Bird.

An NTSB Aviation Accident Report, which provides an analysis of the crash and lists its probable causes, is pending.

A message sent to an NTSB inquiring about the status of the investigation was not immediately returned on Thursday.