The December plane crash in which 62-year-old Mark Matter piloted his Piper into a snow-covered mountain near Aniak was suicide, authorities say.
Matter and his wife, 63-year-old Cecilia Matter, died in the crash of the Piper PA-11.
The Matters took off from Aniak on Dec. 15 and crashed at 2,000 feet elevation on Marvel Dome near the family's mine at Marvel Creek, according to an Alaska State Troopers report.
Friends and family members later told Alaska State Troopers that Cecilia Matter was very sick with cancer.
The National Transportation Safety Board in June released a final report describing the probable cause of the crash as the pilot's "intentional flight of the airplane into terrain in an act of suicide." The plane had no mechanical problems, the report found.
The troopers, in an incident report in June, under the heading "incident activities/offenses" listed causes of death as "manslaughter … intentionally aids suicide" and suicide.
Members of the Matter family — the couple had three adult children — declined to comment last week.
One of their daughters called her parents "inseparable from the beginning" in an interview with Bethel-based radio station KYUK days after they died.
The crash that killed the Matters was the only Alaska incident with a probable cause of suicide that also involved a passenger, according to NTSB Alaska region chief Clint Johnson.
Alaska has had only about three crashes with a probable cause of suicide in the last two decades, Johnson said.
"Then a number of other ones that we suspect it but we were never able to prove it," he said.
An Anchorage man committed suicide in December 2015 when he flew his Cessna 172 into a downtown Anchorage office building where his wife worked. A 40-year-old man wanted on an arrest warrant for arson rented a Cessna 172S and crashed into the water off Whittier in 2000, according to NTSB reports. Investigators learned he left a note with a friend before he got into the plane.
Johnson called the crash that killed the Matters a "very unique situation" and said his agency followed the troopers and the State Medical Examiner's Office on the investigation.
"We gathered our own information, but obviously they have to match," he said.