beast of prey vs persecutor

beast of prey

noun
  • A predatory person, savagely cruel and ruthless in their treatment of others. 

  • A carnivorous animal that hunts for its food, especially one that preys on vertebrates. 

persecutor

noun
  • A person or thing that persecutes or harasses. 

How often have the words beast of prey and persecutor occurred in a corpus of books? (source: Google Ngram Viewer )