burn at the stake vs do away with

burn at the stake

verb
  • To kill (someone) by tying them to a post and setting a fire beneath them 

do away with

verb
  • To have someone killed. 

  • To abolish; to put an end to; to eliminate. 

How often have the words burn at the stake and do away with occurred in a corpus of books? (source: Google Ngram Viewer )