凶手 (xiōngshǒu) means "murderer" or "killer." It combines 凶 (fierce/violent) with 手 (hand/person), referring to the perpetrator of a killing. It is a common term in news reports, crime stories, and legal contexts. A related word is 嫌疑人 (suspect).
警方表示凶手已经被抓获归案。
Jǐngfāng biǎoshì xiōngshǒu yǐjīng bèi zhuāhuò guī'àn.
The police said the killer has been caught and brought to justice.
电影里的凶手竟然是最不起眼的那个人。
Diànyǐng lǐ de xiōngshǒu jìngrán shì zuì bù qǐyǎn de nàge rén.
The killer in the movie turned out to be the most inconspicuous person.
到目前为止,凶手的身份还没有确认。
Dào mùqián wéizhǐ, xiōngshǒu de shēnfèn hái méiyǒu quèrèn.
So far, the identity of the killer has not been confirmed.