Canibal Holocaust

A researcher had a tape, which belongs to a group of 3 men and 1 women, record their expedition in the jungles of South America. The reason of the expedition was to find the tribe which eat people in South America, but that is not true. They have fun and go to a tribal massacre that they do not know. And when they found a cannibal tribe, they also realize that "prey" as they and their tribe massacred their purpose is to find ...