A reward has been raised to $65,000 to whoever locates a plane with four people aboard that's been missing since Aug. 21 in Katmai National Park and Preserve, according to the father of one of those on board. Three National Park Service employees -- Mason McLeod, 26, Neal Spradlin, 28, and Seth Spradlin, 20 --were aboard the de Havilland Beaver when it vanished. The plane was piloted by 47-year-old Marco Alleto.

Searchers found no sign of it after planes repeatedly criss-crossed the region, and last week the official search was called off. The plane was on a short flight over rugged terrain between Swikshak Lagoon and King Salmon.

The father of McLeod, Steve McLeod, a retired police officer who traveled to Alaska from Florida, said Monday that the reward has been increased to $65,000 from $15,000.

Anyone with information about the plane is asked to call the National Park Service at 1-907-246-3305, or the Alaska State Troopers at 1-907-246-3346.