3 sentences

1. 刑警正在现场调查取证。

   xíng​jǐng zhèng​zài xiàn​chǎng diào​chá qǔ​zhèng.

   The criminal police are investigating and collecting evidence at the scene.

   Source: Dong Chinese Dictionary

2. ‎请问你是负责这个案子的刑警吧？

   ‎ qǐng​wèn nǐ shì fù​zé zhè gè àn​zi de xíng​jǐng ba?

   Are you the detective in charge of this case?

   Source: OpenSubtitles

3. 为了及早侦破案件，刑警们已经好几天没睡觉了。

   wèi​le jí​zǎo zhēn pò àn​jiàn, xíng​jǐng men yǐ​jīng hǎo​jǐ tiān méi shuì​jiào le.

   To solve the case as quickly as possible, the criminal police have not slept for several days.

   Source: Dong Chinese Dictionary