NEW DELHI — The young American, paddling his kayak toward a remote Indian island whose people have resisted the outside world for thousands of years, believed God was helping him dodge the authorities.
Indian ships monitor the waters around the island, trying to ensure outsiders do not go near the Sentinelese, who have repeatedly made clear they want to be left alone.
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 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 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."
Indian authorities have been trying to figure out a way to recover Chau's body after he was killed last week by islanders who apparently shot him with arrows and then buried his body on the beach.
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A team of police and officials from the forest department, tribal welfare department and coast guard on Friday launched a second boat expedition to the island to identify where Chau died.
The officials took two of the seven people arrested for helping Chau get close to the island in an effort to determine his route and circumstances of his death, according to a statement issued by police for the Andaman and Nicobar islands, where North Sentinel is located.
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.
"Since the Sentinelese tribespeople are protected by law to preserve their way of life, due precautions were taken by the team to ensure that these particularly vulnerable tribal groups are not disturbed and distressed during this exercise," the statement said. The team returned later Friday.
The police and the coast guard had carried out an aerial survey of Northern Sentinel Island earlier in the week. A team of police and forest department officials also used a coast guard boat to visit the island Wednesday.
Officials typically don't travel to the North Sentinel area, where people live as their ancestors did thousands of years ago. The only contacts, occasional "gift giving" visits in which bananas and coconuts were passed by small teams of officials and scholars who remained in the surf, were years ago.
Police are consulting anthropologists, tribal welfare experts and scholars to figure out a way to recover the body, said Dependera Pathak, director-general of police on the Andaman and Nicobar islands.
Scholars know almost nothing about the island, from how many people live there to what language they speak. The Andamans once had other similar groups, long-ago migrants from Africa and Southeast Asia who settled in the island chain, but their numbers have dwindled dramatically over the past century as a result of disease, intermarriage and migration.
Chau estimated the island had about 250 inhabitants, with at least 10 people living in each hut.
"The tribe's language has a lot of high pitched sounds like ba, pa la and as," he wrote.
It's not clear what happened to Chau when he swam back to the island the next morning. But on the morning of the following day, the fishermen watched from the boat as tribesmen dragged Chau's body along the beach and buried his remains.
Five fishermen, a friend of Chau's and a local tourist guide have been arrested for helping Chau, police say.
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.
Authorities say Chau arrived in the area on Oct. 16 and stayed on another island while he prepared to travel to North Sentinel. It was not his first time in the region: he had visited the Andaman islands in 2015 and 2016.
With help from the friend, Chau paid fishermen $325 to take him there, Pathak said.
After the fishermen realized Chau had been killed, they left for Port Blair, the capital of the island chain, where they broke the news to Chau's friend, who notified his family, Pathak said.
Chau, whose friends described him as a fervent Christian, attended Oral Roberts University in Tulsa, Oklahoma. Before that he had lived in southwestern Washington state and went to Vancouver Christian High School.