The Real Cannibal Ferox

I never really considered that the Cannibal exploitation genre had its basis in anything other than racist myth, my understanding being that cannibalism was restricted to complex cultural rituals for dealing with the dead in some isolated tribal societies. However CNN is reporting a pretty gruesome tribal cannibal murder in the Amazon after which the victim's family "saw his body quartered and his skull hanging on a tree".

I'm intrigued as to how often these reports surface and how many of them turn out to be true. Were the Cannibal exploitation films inspired by reports like this - or more interestingly, are the reports inspired by the films?