Conversation so far:
Why was there a shootout at Pine Ridge?
On June 26, 1975, Special Agents Jack R. Coler and Ronald A. Williams of the Federal Bureau of Investigation were on the Pine Ridge Indian Reservation searching

Question: What were they searching for?
Self-contained rewrite: What were Jack R. Coler and Ronald A. Williams of the Federal Bureau of Investigation on the Pine Ridge Indian Reservation searching for?