red-handed vs with one's trousers down

red-handed

adj
  • Deadly, bloody. 

  • Showing clear evidence of guilt; in the act of wrongdoing. 

  • With hands that are red from blood. 

with one's trousers down

How often have the words red-handed and with one's trousers down occurred in a corpus of books? (source: Google Ngram Viewer )