noun
undercover investigator; decoy investigator
A law enforcement officer who poses as a criminal or victim to gather evidence or make arrests. Often used in the context of sting operations.
おとり捜査官が違法薬物の売人に扮して潜入した。
An undercover investigator infiltrated by posing as an illegal drug dealer.
警察はおとり捜査官を使って売春の取り締まりを行った。
The police conducted a prostitution sting using a decoy investigator.
Compound of おとり (decoy) and 捜査官 (investigator). The word おとり originally referred to a decoy bird used in hunting.