侦查to go and make inquiries; to investigate

• 察访某人的下落

  inquire about a person's whereabouts

• 察访失踪的人

  make inquiries about a missing person

• 察访案情

  make inquires about the details of a case

• 察访民情

  go and investigate the what state the people are in

• 暗中察访

  conduct secret inquiries