明查暗访

Explanation: Out in the investigation, secretly visit. Refers to the various investigations to understand the situation 　　Usage: Joint type; as the predicate attribute; with compliment 　　Source: Qing Liu E, "Travels" section 18 back: "sending you to the East Village conducted a thorough investigation of Qi, which is poison murder of thirteen?" Thesaurus:  Anchamingfang, Thorough investigation