It is unclear what exactly happened to him. For two days, he used a kayak to paddle the half-mile between the boat and North Sentinel, where he rattled off passages from Genesis to the islanders.
Sometimes the islanders simply stared at him. Other times they laughed.
The frustration built. In a 13-page letter Mr. Chau gave to the fishermen, in which he detailed those failures to win over the islanders, he pleaded with God for clarity: “I don’t want to die. Who will take my place if I do?”
On the morning of Nov. 17, the fishermen saw a group of islanders dragging his body on the beach, then burying it in a shallow grave in the sand. The fishermen and one other man who the police say helped Mr. Chau reach the island have been arrested and charged with culpable homicide not amounting to murder and with violating rules protecting aboriginal tribes. Another case has been filed against “unknown persons,” the islanders, for killing Mr. Chau.
The investigation is now heading into uncharted territory. On Friday, authorities sent police officers, along with some of the arrested fishermen, on a boat to observe North Sentinel and establish where Mr. Chau was killed. But will any of the islanders actually face prosecution? And if arrested, would they die in captivity from disease, their immune systems no match for modern microbes?
In 2006, two crab fishermen were killed by islanders after washing up on North Sentinel’s shores. Police officials are now poring through the records of those killings, looking for clues about what happened to the fishermen’s bodies.
Mr. Pathak said that about a week after the islanders buried the fishermen in shallow graves on the beach, they dug up the bodies and stood them up by tying them to lengths of bamboo.
“If they follow the same pattern,” Mr. Pathak said, they may soon take out Mr. Chau’s body, although he suggested that it might never be recovered. In the case of the two fishermen, Mr. Pathak doesn’t think their bodies were ever recovered and he seemed to indicate that was a possibility in this case as well. “If maybe, from a distance, we can see John’s body, then at least his death gets fully established,” he said.
In his last letter, Mr. Chau was clear about what he wanted done in case he died. “Don’t retrieve my body,” he wrote, underlining it. “This is not a pointless thing — the eternal lives of this tribe is at hand.”