Liza Ryan knows murdered Christian missionary John Chau. Not the person — the type.

"This guy feels totally familiar," she says.

Key points: Chau grew up on Robinson Crusoe tales and believed he was specially chosen

Chau grew up on Robinson Crusoe tales and believed he was specially chosen There are more than 1.6 million Americans going on short missions every year

There are more than 1.6 million Americans going on short missions every year North Sentinelese are infamous for their hostility to the outside world

Ryan spent more than seven years as a missionary and says his story is one she has come across many times before.

"Often very young men, typically white, though John Chau is mixed, that tend to be adventurous and [seek] anything that can involve war or missions — it attracts guys that really want to be out there and do something," she says.

Last week John Allen Chau's adventures came to a dark end on the shores of remote North Sentinel Island in the Indian Ocean where he had travelled illegally to try and convert the notoriously hostile islanders.

According to the Centre for the Global Study of Christianity, there are 440,000 missionaries in foreign countries, but this figure refers to long-term professional missionaries.

The Sentinelese stand guard on an island beach. North Sentinel Island. ( Supplied: Christian Caron )

Experts actually estimate that there are more than 1.6 million young Americans going abroad on short missions for weeks or months every year.

Ryan even grew up in the same state as Chau, living just under five hours' drive away from each other in the state of Washington.

"I guess maybe the general public is not used to seeing a young, attractive guy going out and wanting to be in missions," she says.

"But that is quite typical. I know hundreds and hundreds of those, who would go into a place like that."

'My name is John, I love you'

Chau's diary entries provide a detailed and intimate insight into his frame of mind right before he died.

Loading...

"I hollered: 'My name is John, I love you and Jesus loves you," he wrote of his first meeting with the Sentinelese.

"I don't want to die. Would it be wiser to leave and let someone else continue? No. I don't think so."

Even more revealing was a throwaway line in an interview Chau did with an adventure blog a few years ago.

"Growing up, I remember dusting off a massive tome in my dad's downstairs study titled Robinson Crusoe," he told The Outbound Collective in 2015.

"I started reading easier kid-friendly books like Hatchet, My Side of the Mountain, and Sign of the Beaver, the latter of which inspired my brother and I to paint our faces with wild blackberry juice and tramp through our backyard with bows and spears we created from sticks."

Chau grew up on stories of first contact and adventurers like Robinson Crusoe and his Man Friday. ( Instagram: jonachau )

Crusoe who was described as the "true prototype of the British colonist" by writer James Joyce, saves a native man — who he names Friday — from his "savage" existence by exposing him to Western culture.

However, this world that clearly inspired the imagination of Chau no longer exists, says professor of American studies and international affairs at George Washington University, Melani McAlister, who describes Chau's actions as a kind of "performative fantasy".

"It's breathtakingly naive — he is showing up and talking about Jesus in a language these people don't even speak," she tells the ABC.

"This guy seems to me to be enacting a fantasy of first contact that is almost impossible to have anywhere in the world anymore."

White saviour complex is a term which originates from English writer Rudyard Kipling's poem The White Man's Burden about saving dark skinned people from themselves through the superiority of Western culture.

Historian Dr Laura Rademaker from the Australian National University has studied missions in the 20th century in Indigenous communities and says missionaries have always depended on local goodwill, mediators and invitations.

Chau was killed by arrows shortly after setting foot on the island on November 19. ( Supplied: Andaman and Nicobar Police )

"You have this narrative of people barging into local communities, but quite often it's been much more complex," she says.

"Missionaries still needed to find people to act as intermediaries or translators and patrons in some way.

"When they haven't done that they fail very quickly and they won't get any converts, plus they'll face passive or even violent resistance like we saw in the [Chau] case."

A faith, a culture and identity in one

No longer a missionary or even an evangelical Christian, Liza Ryan — who describes herself as "post-evangelical" — says her former world was not just a spiritual belief system but a culture and an entire identity.

"There is very much an American DNA in it and a push for a kind of American foreign ideal that is projected onto others," she says.

Professor McAlister says that in the past missionaries were chosen very formally and went on missions for life after being vetted and trained by large organisations.

John Allen Chau's Instagram is filled with images of his journeys to exotic locations. ( Instagram: johnachau )

"In the last 20 years it's become very free flowing," she tells the ABC.

"Now they tend to be much shorter term and they could be sent by an individual church — most people who do missionary work now do just [a few] weeks."

Chau had been trained by the evangelical missionary group All Nations based in Kansas City in the US.

According to its website it provides evangelism training to those who want to go "on missions to make disciples".

For Chau though, his trip to North Sentinel island to convert the Sentinelese was his own personal mission, and one he had fantasised about for years.

"God, I thank you for choosing me before I was even yet formed in my mother's womb to be your messenger of your good news to the people of North Sentinel island," he scrawled in pencil in the pages of his journal shortly before his death.

There is a stark contrast between professional missionaries who enter countries legally, undergo training in language and cultural sensitivity and those who just turn up with a bible and their love for Jesus, says Peter Rodgers the international director of the Church Missionary Society of Australia.

North Sentinel Island is approximately 60 square kilometres and the exact population is unknown. ( AP: Gautam Singh )

"Every worker [we employ] needs a valid visa to do that work, and to do the work that visa allows and [they need to be] welcomed into the country," he tells the ABC.

"They do a five-month course in intercultural studies in how to respect another culture and how to understand another culture."

Forbidden fruit is sweeter

There are at least 39 countries where it is illegal to undertake missionary conversion work and many more where it is heavily restricted, according the US State Department's 2017 Freedom of Religion report.

Just this week an Australian woman was arrested in Nepal and deported for trying to convert locals; she was found with bibles and other religious materials and had reportedly been knocking on doors trying to convert people.

In Malaysia last week four Finnish nationals were arrested after they were caught handing out Christian materials and pens with biblical quotes and allegedly harassing people in the Muslim-majority country.

Professor Melani McAlister says the cachet attached to proselytising in these places holds high appeal for the more adventurous of missionaries.

John Chau while guiding students around Mount Adam the US in August, 2018. ( Instagram: jonachau )

"A lot of people do get in trouble with these kind of situations, North Korea for example," she says.

"They are almost always doing it outside of official channels."

Chau seemed to see North Sentinel Island as the ultimate mission and seemed to think he was the only person who could succeed in converting the Sentinelese.

"God, I don't want to die," Chau scribbled in his journal just before he died. "WHO WILL TAKE MY PLACE IF I DO?"

Dr Laura Rademaker says the focus should be on managing those that do this kind of work.

"Missionaries have tended to operate on an assumption that they have a universal truth and that all people would welcome this truth," she says.

"Yes, there is a white saviour complex but it cuts both ways — how can you restrict people's religious freedom?

"There is always going to be missionaries and maybe it is better to think about how we can manage them because it is not going to go away."

John Allen Chau was killed when he went ashore on North Sentinel Island. ( Instagram: johnachau )

For professional missionaries like Peter Rodgers it is a tragic story, but not one that is representative of missionary work in his experience.

"He was a courageous man — what can I say, but we would not work that way."

"Gone are the days of going in from the west with Western ways and Western money."

This story was completed using sources from the 2018 East West Centre's Senior Journalism Seminar.