The killing this month of an American missionary, John Allen Chau, on an remote island in the Andaman Sea has prompted an international debate over the role of missionaries around the world and how police should respond to Mr. Chau’s death.

Mr. Chau ventured to North Sentinel — an island that is home to one of the world’s last undiluted tribes of hunter-gatherers and, by Indian law, off limits to outsiders — to spread Christianity there.

As the police investigation unfolds, The Times would like to better understand the views and efforts of missionaries today.