案件 (ànjiàn) means "case," typically referring to a legal case or criminal incident. It is used in formal and news contexts when discussing crimes, investigations, or court proceedings.
警方正在调查这起案件。
Jǐngfāng zhèngzài diàochá zhè qǐ ànjiàn.
The police are investigating this case.
这个案件非常复杂,涉及很多人。
Zhège ànjiàn fēicháng fùzá, shèjí hěn duō rén.
This case is very complex and involves many people.
法院今天审理了一起盗窃案件。
Fǎyuàn jīntiān shěnlǐ le yī qǐ dàoqiè ànjiàn.
The court heard a theft case today.