5 sentences

1. 他在当地的公安分局工作。

   tā zài dāng​dì de gōng'ān fēn​jú gōng​zuò.

   He works at the local public security sub-bureau.

   Source: Dong Chinese Dictionary

2. 他是一名公安，平日里工作非常繁忙。

   tā shì yī míng gōng'ān, píng​rì lǐ gōng​zuò fēi​cháng fán​máng.

   He is a public security officer, and his daily work is very busy.

   Source: Dong Chinese Dictionary

3. 公安机关决定对这起合同诈骗案立案侦查。

   gōng'ān jī​guān jué​dìng duì zhè qǐ hé​tong zhà​piàn'àn lì'àn zhēn​chá.

   The public security organs decided to file a case for investigation into this contract fraud.

   Source: Dong Chinese Dictionary

4. 广大公安干警日夜奋战在维护社会治安的第一线。

   guǎng​dà gōng'ān gàn​jǐng rì​yè fèn​zhàn zài wéi​hù shè​huì zhì'ān de dì​yī​xiàn.

   The vast ranks of public security officers fight day and night on the front lines of maintaining social order.

   Source: Dong Chinese Dictionary

5. 警察的首要任务是维护公安，保障广大居民的生命安全。

   jǐng​chá de shǒu​yào rèn​wu shì wéi​hù gōng'ān, bǎo​zhàng guǎng​dà jū​mín de shēng​mìng ān​quán.

   The primary task of the police is to maintain public security and ensure the safety of the residents.

   Source: Dong Chinese Dictionary