Jason Miller made his acting debut in 1973, as the troubled Father Karras in the horror classic "The Exorcist", and he immediately received an Academy Award nomination for it. It's bizarre that, barely 4 years later, he appears in this grim and obscure Spanish political thriller/exploitation flick. It's a very unusual but nevertheless courageous role, since Miller depicts a political prisoner in an undisclosed South American country under dictatorship. He manages to escape during a transport, but promptly finds himself relentlessly pursued by an evil warden and his vicious dog; - and later just by the vicious dog. "El Perro", also known as "A Dog Called Vengeance", is a raw and mean-spirited drama; - ugly and deeply unpleasant to look at, but simultaneously intriguing. The film is long and contains slightly two many tedious sequences, but the essential sequences (as in: the dog-chasing) are intense and perplexing. The last half hour, when the action transfers from the vile and humid jungle to the big and corrupt city, I found very difficult to sit through because it's almost purely talkative and hardly any action. The titular dog, a magnificent German Shepard, is genuinely impressive animal.