Indian officers had a nervous long-distance face-off with the tribe who killed an American missionary, in their latest bid to locate his body on a remote island, police said.

The police team, who took a boat just off Indian-owned North Sentinel island on Saturday, spotted men from the Sentinelese tribe on the beach where John Allen Chau was last seen, the region’s police chief Dependra Pathak told AFP.

Using binoculars, officers — in a police boat about 400 metres from the shore — saw the men armed with bows and arrows, the weapons reportedly used by the isolated tribe to kill Mr Chau as he shouted Christian phrases at them.

“They stared at us and we were looking at them,” Mr Pathak said. The boat withdrew to avoid any chance of a confrontation.

DISEASE FEARS
There are fears 21st century diseases such as the mild common cold could kill off the tribe.

Vice reported it is illegal to make contact with the Sentinelese people, who “are not immune to anything.

Something as simple as a common flu could threaten to wipe out their ancient tribe of 50 to 150 people altogether, Vicereported.

For that same reason, retrieving Mr Chau remains is proving difficult for authorities.

“They [the Sentinelese] are not immune to anything,” said PC Joshi, an anthropology professor at Delhi University. “A simple thing like flu can kill them.”

MYSTERY TRIBE
The death of the 27-year-old on November 17 has cast a new spotlight on efforts to protect one of the world’s last “uncontracted” tribes, whose language and customs remain a mystery to outsiders.

Fishermen who took Mr Chau to North Sentinel — which is one of the Andaman and Nicobar Islands in the Bay of Bengal — said they saw the tribe burying the body on the beach.

The Sentinelese normally attack anyone who goes to the island and Mr Pathak said police were monitoring to see if there was a repeat of an incident after two fishermen who strayed onto the island were killed in 2006.

One week after their deaths, the bodies of the two Indians were hooked on bamboo stakes facing out to sea.

“It was a kind of scarecrow,” Mr Pathak said.

“We are studying the 2006 case. We are asking anthropologists what they do when they kill an outsider,” the police chief added.

“We are trying to understand the group psychology.”

ANOTHER WORLD
Dependra Pathak is the director-general of police of the Andaman and Nicobar Islands where North Sentinel is located.

“We have more or less identified the site and the area in general,” Mr Pathak said.

“They were patrolling the beach, at the same spot John was killed, with weapons,” he said, according to the New York Times.

“Had we approached … they would have attacked. This case is the strangest and toughest in my life,” Mr Pathak said. “We are trying to enter into another civilisation’s world.”

Though Mr Chau’s death is officially a murder case, anthropologists say it may be impossible to retrieve the American’s body and that no charges will be made against the protected tribe.

Seven people, including six fishermen who were involved in ferrying Mr Chau to North Sentinel, have been arrested.

The fishermen have accompanied the police teams to the island to help efforts to pinpoint where Mr Chau was killed.

Anthropologists and tribal welfare experts who have had the previous rare contacts with the Sentinelese have been heavily involved with the inquiry.

“Their advice will be important,” Mr Pathak said.

“We are taking the advice of the people in the field to advance this case.”

WANTED TO SHARE ‘LOVE OF JESUS’
Mr Chau went to “share the love of Jesus,” said Mary Ho, international executive leader of All Nations.

All Nations, a Kansas City, Missouri-based organisation, helped train Mr Chau, discussed the risks with him and sent him on the mission, to support him in his “life’s calling,” she added.

“He wanted to have a long-term relationship, and if possible, to be accepted by them and live among them,” she said.

When a young boy tried to hit him with an arrow on his first day on the island, Chau swam back to the fishing boat he had arranged to wait for him offshore. The arrow, he wrote, hit a Bible he was carrying.

“Why did a little kid have to shoot me today?” he wrote in his notes, which he left with the fishermen before swimming back the next morning.

“His high-pitched voice still lingers in my head.”

Police say Mr Chau knew that the Sentinelese resisted all contact by outsiders, firing arrows and spears at passing helicopters and killing fishermen who drift onto their shore.

His notes, which were reported Thursday in Indian newspapers and confirmed by police, make clear he knew he might be killed. “I DON’T WANT TO DIE,” wrote Mr Chau, who appeared to want to bring Christianity to the islanders.

“Would it be wiser to leave and let someone else to continue. No I don’t think so.” Mr Chau paid fishermen to take him near North Sentinel, using a kayak to paddle to shore and bringing gifts, including a football and fish.

The Indian government lifted restrictions on travelling to the island in August, Ms Ho said. She said she couldn’t comment on why Mr Chau arrived there the way he did, but that he carefully planned it.

The Sentinelese are thought to have lived on the island for 30,000 years but have had very little contact with outsiders.

North Sentinel island is part of the far flung Andaman Islands in the vast Bay of Bengal. The region is home to five Stone Age tribes — which anthropologists believe to be the last of their kind and are dwindling in numbers.

While the Sentinelese have been cut off from the rest of the world for decades they are a protected group under the government of India, which lies to the West of the island.