abbreviation for confidential informant: a person who secretly gives information to the police about criminal activity

She worked for years as an active CI, and still called occasionally with tips on various cases. 她作为一名活跃的秘密线人工作了多年，现在仍然偶尔打电话为各种案件提供线索。

Information provided by a CI was put before the jury. 一名秘密线人提供的信息被提交给了陪审团。