An Indian Coast Guard helicopter sent to retrieve the bodies was repelled by a volley of arrows from the community, believed to be the last pre-Neolithic tribe in the world. According to AFP's law enforcement sources, things immediately became unsafe.
Chau, who according to Indian media was a Christian missionary, had offered local fishermen money to take him to the island, the source said.
Police have launched a murder investigation, but the Sentinelese can not be prosecuted.
North Sentinel is in the Andaman Islands at the intersection of the Bay of Bengal and Andaman Sea. But then he tried again two days later.
North Sentinel Island is about 50km (31 miles) west of Port Blair, the capital of the island cluster.
After the fishermen dropped him off, they reportedly saw him get struck by arrows but keep walking.
The fisherman saw the people dragging Chau's body, AFP reports, causing them to flee.
The Sentinelese people live on their own small, forested island and are known to resist all contact with outsiders, often attacking anyone who comes near.
There are also fears that any outside contact with the group, who are thought to have resided on North Sentinel Island for sixty thousand years, could expose them to diseases for which the tribe has no immunity.
Yadav said that Chau and the fishermen arrived at the island around midnight on November 14.
Indian media suggested that Chau had a desire to meet the tribes in order to preach Christianity to the island tribes, and that his body was found by the fishermen.
The BBC quoted a local journalist who said that "p$3 olice said Chau had previously visited North Sentinel island about four or five times with the help of local fishermen". "It's in fact illegal to have any sort of contact with them", Bhaumik said.
He had earlier visited the Andaman and Nicobar Islands in 2015 and 2016, Pathak said.
The Sentinelese people have lived on the island for almost 55,000 years and fiercely reject contact with the outside world, according to the human rights charity Survival International.
The population of the tribe is not clear, but was "declining", social scientist Shiv Viswanathan said, according to the AP. They are protected by Indian law.
In an Instagram post, his family said it was mourning him as a "beloved son, brother, uncle and best friend to us".
A 27-year-old American man was killed on Wednesday by untouched tribesmen after he attempted to venture into their territory of remote North Sentinel Island in the Andaman islands. In 2006, two fishermen were killed after their boat accidentally floated in the vicinity of the island.
"This tragedy should never have been allowed to happen", Stephen Corry, Survival International's Director, said in a statement.