the official organization that is responsible for protecting people and property, making people obey the law, finding out about and solving crime, and catching people who have committed a crime

I think you should call the police. 我认为你应该报警。

The police are investigating fraud allegations against him. 警方在调查对他的欺诈指控。

members of this organization

There should be more police patrolling the area on foot. 应该增加警力在这一地区步行巡逻。

to control or guard a public event or area by using members of the police or a similar force

The march will be heavily policed by an anti-riot unit. 防暴警察将对示威游行进行严密警戒。

to control the way in which a possibly dangerous substance is dealt with or a dangerous activity is done

The use of these chemicals must be carefully policed. 这些化学药品使用时必须受到严格控制。