undercover agent 臥底

undercover agent
繁：臥底
简：卧底

據悉，該名卧底警員，潛伏黑幫和勝和期間，曾數度墮入險境，被黑幫不斷試探，飽受考驗，幫會中人查不出他是卧底身份，竟仍懷疑他是「二五仔」。

卧底潛伏一年瘦40磅（2017年8月9日）。蘋果日報，取自 https://hk.news.appledaily.com/local/daily/article/20170809/20116263

A district councillor and an alleged leader of the Wo Shing Wo triad society were among almost 300 people arrested on Monday and Tuesday during the culmination of one undercover agent’s 11-month operation within Hong Kong’s criminal circles.

Hong Kong district councillor among 299 arrested after officer’s undercover triad investigation. (2017, August 8). South China Morning Post. Retrieved from http://www.scmp.com/news/hong-kong/law-crime/article/2105984/hong-kong-district-councillor-among-299-arrested-after