Fraud of 2000 yuan can be filed. It would be much easier if he really worked in the Public Security Bureau. You can ask him to go to his company, and if he doesn't pay back the money, he can sue him in court. I'm sure he won't lose face for thousands of dollars. If he hasn't paid you back a penny, it's not actively preparing for repayment, it's obvious fraud.
But it is not difficult to buy police uniforms now. It's a joke to infer from clothes alone.