Indian authorities are struggling to figure out how to recover the body of John Chau, who was killed after wading ashore on an island cut off from the modern world.

Key points: Police are consulting with anthropologists, tribal welfare experts and scholars on how to recover Mr Chau's body

Police are consulting with anthropologists, tribal welfare experts and scholars on how to recover Mr Chau's body Police surveyed the island by air on Tuesday, and a team of police and forest department officials used a coast guard boat to travel there on Wednesday

Police surveyed the island by air on Tuesday, and a team of police and forest department officials used a coast guard boat to travel there on Wednesday North Sentinel islanders are cut off from the modern world so "a simple flu can kill them"

Mr Chau was killed last week by North Sentinel islanders who apparently shot him with arrows and then buried his body on the beach, police say.

But even officials do not travel to North Sentinel, where people live as their ancestors did thousands of years ago, and where outsiders are seen with suspicion and attacked.

"It's a difficult proposition," said Dependera Pathak, director-general of police on India's Andaman and Nicobar Islands, where North Sentinel is located.

"We have to see what is possible, taking utmost care of the sensitivity of the group and the legal requirements."

Police are consulting anthropologists, tribal welfare experts and scholars to figure out a way to recover the body, he said.

While visits to the island are heavily restricted, Mr Chau paid fishermen last week to take him near North Sentinel, using a kayak to paddle to shore and bringing gifts including a football and fish.

It was "a foolish adventure," said PC Joshi, an anthropology professor at Delhi University who has studied the islands.

"He invited that aggression."

Professor Joshi noted that the visit not only risked Mr Chau's life, but also the lives of islanders who have little resistance to many diseases.

"They are not immune to anything. A simple thing like flu can kill them," he said.

On his first day Mr Chau interacted with some tribesmen — who survive by hunting, fishing and collecting wild plants — until they became angry and shot an arrow at him.

The 26-year-old self-styled adventurer and Christian missionary then swam back to the fishermen's boat waiting at a safe distance.

That night, he wrote about his visit and left his notes with the fishermen. He returned to North Sentinel the next day (November 16).

What happened then is not known, but on the morning of the following day, the fishermen watched from the boat as tribesmen dragged Mr Chau's body along the beach and buried his remains.

The tribespeople of North Sentinel Island are susceptible to diseases because of their isolation. ( Supplied: Christian Caron )

Mr Pathak said seven people have been arrested for helping Mr Chau, including five fishermen, a friend of Mr Chau's and a local tourist guide.

Mr Chau was apparently shot and killed by arrows, but the cause of death cannot be confirmed until his body is recovered, Mr Pathak said.

He also said the police were examining whether Mr Chau had tried earlier to visit the isolated island.

Trip to isolated island was well planned

John Chau's friends have described him as courageous and compassionate. ( Instagram: johnachau )

Mr Pathak said Mr Chau and his accomplices planned well for last week's visit by "camouflaging the visit as fishing".

Also, Mr Chau appeared to be full of confidence as he wrote in his notes, "God sheltered him from coastguard and Navy," he said.

Loading...

In an Instagram post, his family said it was mourning him as a "beloved son, brother, uncle and best friend to us."

The family also said it forgave his killers and called for the release of those who assisted him in his quest to reach the island.



"He ventured out on his own free will and his local contacts need not be persecuted for his own actions," the family said.

Police surveyed the island by air on Tuesday (local time), and a team of police and forest department officials used a coast guard boat to travel there on Wednesday. Another trip was planned on Thursday.

India recently changed some of its rules on visiting isolated regions in the Andamans.

While special permits are required, scholars say visits are now theoretically allowed in some parts of the Andamans where they used to be entirely forbidden, including North Sentinel. Mr Chau had no permit, police said.

Mr Chau had wanted ever since high school to go to North Sentinel to share Christianity with the indigenous people, said Mat Staver, founder and chairman of Covenant Journey, a program that takes college students on tours of Israel to affirm their Christian faith.

Mr Chau went through that program in 2015.

"He didn't go there for just adventure. I have no question it was to bring the gospel of Jesus to them," Mr Staver said.

Authorities need to recover body to understand exactly what happened on the island. ( Supplied: Indian Coastguard/Survival International )

AP