He was in command of a fleet of C-47 transport planes flying supplies from Leyte to the island of Mindanao and crashed in a remote jungle on Leyte while transporting a load of gasoline. There were six crew members aboard the plane, all of whom perished in the crash.

In 1989, forty-four years later, remains from the crash were found and sent to an Army Air Base in Manila and from there were eventually sent to Hawaii where, through DNA testing, a positive identification was made of four of the six crew members, Captain Grismore being one of them.

Sources:
http://www.legacy.com/obituaries/saltlaketribune/obituary.aspx?n=george-grismore&pid=146545458
http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=56782683
http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=74035824
https://www.abmc.gov/node/357261#.VuOFpzaBe0g
http://www.pacificwrecks.com/aircraft/c-47/42-100455.html

Grismore, George Willard, Capt