Transcript for Slain US missionary's 'desire was to befriend' tribespeople

Moving on now overseas to the troubling developments on a far away island. A young American on an E value jell call mission. His adventure taking a harrowing turn. What he wrote in those final moments. Here's ABC news foreign correspondent James Longman. Reporter: Tonight, this remote island in the Indian ocean is the focus of a search for the body of an American missionary who police believe was killed by an endangered tribe. 26-year-old John CHAU traveled the world preaching christianity, documenting his journey on Instagram. Officials believe he paid local fisherman to drop him off illegally at the restricted north sentinel island. To an indigenous tribe who has fiercely resisted contact with outsiders. One member can be seen here firing arrows at a relief helicopter after the 2004 tsunami. His desire was to befriend them, he brought gifts to them but unfortunately, as we now know, that didn't happen. Reporter: When the fishermen returned two days later, they thought they saw CHAU's body being buried on the shore. Police say he was likely killed by the tribesmen. In excerpts from CHAU's journals published by "The Washington post", CHAU writes that a tribesman shot at him with an arrow, piecing his waterproof bible. "You guys might think I'm crazy in all this" he wrote in his last message to family "But I think it's worthwhile to declare Jesus to these people" adding "God, I don't want to die." He also reportedly told his mother, "Please don't be angry at them or god if I die." Tonight, CHAU's family saying they forgive those reportedly responsible for his death. Tonight local authorities are working with experts on this tribe to figure out how to move forward. Whit? James, thank you. In California tonight, the death toll rising again, from

This transcript has been automatically generated and may not be 100% accurate.