Aaron Ahkau Matapa Patiole, who was from Australia, was walking with his companion in Upolu when he was struck.
Patiole had been serving in the Samoa Apia Mission since December 2016, according to Eric Hawkins, a spokesman for The Church of Jesus Christ of Latter-day Saints.
“We are grieved by his loss and extend our prayers and love to his family and loved ones,” Hawkins said in a news release. “We pray they will be blessed with peace as they mourn the loss of this valiant young man.”