American missionary John Allen Chau was reportedly obsessed with visiting the remote North Sentinel Island to try to lead the inhabitants to Jesus.
A friend of Chau's told The Washington Post that Chau spent years researching the group, who live in isolation and are known to attack anyone who comes near them.
“He lost his mind, definitely,” friend Remco Snoeij said. “But ask any adventurer. You have to lose your mind a little bit, otherwise, you don’t do it.”
Snoeij told the paper he tried to warn Chau about the tribespeople's penchant for killing outsiders who dare set foot on the island, but if anything that only seemed further ignite his interest.
When he set out for the island, Chau knew his life was at risk, and he carefully documented the trip in journal entries.
“He didn’t want any hearts broken should something go wrong," another friend, John Middleton Ramsey, told the Post. "He was very much aware of what he was doing."
On Chau's first attempt at speaking with the tribe, he was shot at and managed to retreat.
“If you want me to get actually shot or even killed with an arrow then so be it,” he wrote in his journal, addressing God. “I think I could be more useful alive though … I don’t want to die. Would it be wiser to leave and let someone else continue? No. I don’t think so.”
He also wrote to his parents, imploring them not to be angry should he lose his life.
“You guys might think I’m crazy in all this, but I think it’s worth it to declare Jesus to these people,” he wrote. “Please do not be angry at them or at God if I get killed. ... This is not a pointless thing. The eternal lives of this tribe is at hand and I can’t wait to see them around the throne of God worshiping in their own language.”
Chau reportedly paid local fisherman $325 to illegally take him to waters just off the island on Nov. 15. From there, police said, he boarded a kayak and paddled to shore, bearing gifts of a football and fish.
After his first interaction with the tribe, he gave pages from his journal to the fishermen and again set off for North Sentinel Island, according to police. What happened afterward is not known.
The fishermen have been arrested for helping Chau reach the island.
Authorities have yet to retrieve Chau's body.