cross-question vs investigate

cross-question

verb
  • to subject to close questioning. 

noun
  • a question asked during a cross-examination 

investigate

verb
  • To conduct an inquiry or examination. 

  • To inquire into or study in order to ascertain facts or information. 

  • To examine, look into, or scrutinize in order to discover something hidden or secret. 

How often have the words cross-question and investigate occurred in a corpus of books? (source: Google Ngram Viewer )