Who are the Sentinelese, tribe that killed an American in Andaman?

The Sentinelese are an indigenous tribe who have been residing on the North Sentinel Island of the Andaman for over 55,000 years. Their population is estimated to be between 40 and 500, and are known to reject any contact with the outside world. Following the 2004 tsunami, a Sentinelese tribesman was filmed firing arrows at a Navy helicopter on patrol.