Last week, reports emerged that 26-year-old John Allen Chau was killed, when the American visited the tribespeople of the remote North Sentinel Island in an attempt to convert them to Christianity, ignoring numerous warnings of the tribe's hostility to outsiders.

Chau's final letter to his family, According to the Washington Post, read, "You guys might think I'm crazy in all of this but I think it's worthwhile to declare Jesus to these people ... God, I don't want to die."

In the aftermath of his death, Indian police (the nearest authorities to the Andaman and Nicobar Islands), disclosed that the difficult relationship with the Sentinelese and any visitors means that it may be impossible to recover Chau's body from the island.

Now, it has been revealed that prior to his expedition, Chau had an intense obsession with the secluded people. Remco Snoeij met John in 2016, when he sought to learn how to scuba dive on the nearby Havelock Island. Even back then, he showed an interest in the North Sentinelese tribe.

“He shared a keep interest in researching and knowing more about them,” Mr Snoeij told The Washington Post.

The pair went on dive excursions together, where Mr Snoeij reportedly told him about fisherman who had reached the island in 2006, only to be killed by islanders - as well as rumours that the Japanese military had buried gold there during the second world war. “It must have struck a cord,” he said.

Back in 2016, Chau joined the All Nations missionary group, whose international executive leader is Mary Ho. She spoke to the paper about Chau, who she described as having a "radical call" to discover "unreached groups", and claimed he had planned to live there for years to learn their language.

“You could see that every decision he has made, every step he has taken since then was driven by his desire to be among the North Sentinelese people,” Ms. Ho said.

That same year, Chau told another friend, John Ramsey, that he was avoiding becoming romantically involved with anyone before his trip to the island. “He knew of the dangers of this place,” John said. “He didn’t want any hearts to get broken should something go wrong.

"He was very much aware of what he was doing. He also knew it wasn’t exactly legal.”

It was on November 14, that he first headed to the island, paying fisherman to take him by boat. His diary claims he saw men armed with bows and arrows that night, and yelled to them "My name is John, I love you and Jesus loves you".

The following day he returned, at which point the tribe fired arrows at him, one of which - according to reports - even pierced his bible. Then, on November 16, he made his final trip. He asked fishermen to drop him off on the island, where he was killed by arrows; his body dragged and buried in the sand.

“He lost his mind, definitely,” Mr Snoeij said. “But ask any adventurer. You have to lose your mind a little bit, otherwise you don’t do it.”

Last week, reports emerged that 26-year-old John Allen Chau was killed, when the American visited the tribespeople of the remote North Sentinel Island in an attempt to convert them to Christianity, ignoring numerous warnings of the tribe's hostility to outsiders.

Chau's final letter to his family, According to the Washington Post, read, "You guys might think I'm crazy in all of this but I think it's worthwhile to declare Jesus to these people ... God, I don't want to die."

In the aftermath of his death, Indian police (the nearest authorities to the Andaman and Nicobar Islands), disclosed that the difficult relationship with the Sentinelese and any visitors means that it may be impossible to recover Chau's body from the island.

Now, it has been revealed that prior to his expedition, Chau had an intense obsession with the secluded people. Remco Snoeij met John in 2016, when he sought to learn how to scuba dive on the nearby Havelock Island. Even back then, he showed an interest in the North Sentinelese tribe.

“He shared a keep interest in researching and knowing more about them,” Mr Snoeij told The Washington Post.

The pair went on dive excursions together, where Mr Snoeij reportedly told him about fisherman who had reached the island in 2006, only to be killed by islanders - as well as rumours that the Japanese military had buried gold there during the second world war. “It must have struck a cord,” he said.

Back in 2016, Chau joined the All Nations missionary group, whose international executive leader is Mary Ho. She spoke to the paper about Chau, who she described as having a "radical call" to discover "unreached groups", and claimed he had planned to live there for years to learn their language.

“You could see that every decision he has made, every step he has taken since then was driven by his desire to be among the North Sentinelese people,” Ms. Ho said.

That same year, Chau told another friend, John Ramsey, that he was avoiding becoming romantically involved with anyone before his trip to the island. “He knew of the dangers of this place,” John said. “He didn’t want any hearts to get broken should something go wrong.

"He was very much aware of what he was doing. He also knew it wasn’t exactly legal.”

It was on November 14, that he first headed to the island, paying fisherman to take him by boat. His diary claims he saw men armed with bows and arrows that night, and yelled to them "My name is John, I love you and Jesus loves you".

The following day he returned, at which point the tribe fired arrows at him, one of which - according to reports - even pierced his bible. Then, on November 16, he made his final trip. He asked fishermen to drop him off on the island, where he was killed by arrows; his body dragged and buried in the sand.

“He lost his mind, definitely,” Mr Snoeij said. “But ask any adventurer. You have to lose your mind a little bit, otherwise you don’t do it.”