An American Christian missionary is believed to have been killed by the Sentinelese people of North Sentinel island — among the most remote and isolated peoples anywhere on the planet.

North Sentinel Island, located in the Bay of Bengal and technically falling under the jurisidiction of the Indian government, has been home to an isolated tribe of uncontacted humans for tens of thousands of years, who live today very much as they have throughout the majority of that time. Very little is known about these people, in large part because early attempts at contact were met with immediate violence from the tribespeople. In the years since, the Indian government has banned travel to the island in the Andaman Island chain not only for the safety of the passengers, but over concerns that the isolated population will lack the immunity necessary to survive contact with the modern world.

The as-yet-unidentified American was said to be 27-years-old. He traveled to the island illegally, hiring local fisherman to take him to the remote island with the expressed intent of converting the isolated tribe to Christianity.

“We refuse to call him a tourist. Yes, he came on a tourist visa but he came with a specific purpose to preach on a prohibited island,” Dependra Pathak, Director General of Police of the Andaman and Nicobar islands, said.