investigation

noun

1. (countable, uncountable)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.”

   “carry out an investigation”

   “the matter is awaiting investigation”

   “The case is still under investigation.”