2.Plain clothes policeman who work undercover to detect crime.
隐蔽调查犯罪的便衣警察。
例句：
Sean has been a member of the vice squad for nine years.
西恩在缉捕队工作已经9年了。
2.Plain clothes policeman who work undercover to detect crime.
隐蔽调查犯罪的便衣警察。
例句：
Sean has been a member of the vice squad for nine years.
西恩在缉捕队工作已经9年了。
