investigation

noun

Etymology: From Middle English investigacioun, from Old French investigacion, from Latin investigatio. Morphologically investigate + -ion.

1. The act of investigating; the process of inquiring into or following up; research, especially patient or thorough inquiry or examination

   “The investigation into the crime has led to various leads as well as plenty of dead ends.”

   “Despite thorough investigation, the perpetrator of the attacks remains unknown.”