An American is believed to have been killed by an isolated Indian island tribe known to fire at outsiders with bows and arrows, police said on Wednesday.

Police officer Vijay Singh said seven fishermen have been arrested for facilitating the American’s visit to North Sentinel Island, where the killing apparently occurred. Visits to the island are heavily restricted by the government.

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.

The Andaman and Nicobar Islands are a group of islands at the juncture of the Bay of Bengal and Andaman Sea.

Indian media reports said the American was on an adventure trip to the islands and his body was found by the fishermen. However, Singh said the police were in the process of recovering the body.

Singh said the man was killed on Saturday. He declined to give any other details, saying he was investigating the case.

Poachers are known to fish illegally in the waters around the island, catching turtles and diving for lobsters and sea cucumbers. Tribespeople killed two Indian fishermen in 2006 when their boat broke loose and drifted onto the shore.