If it does not conform to the law of fraud, you entrust the case to a local lawyer, which is the lowest cost. There is no need for transportation or accommodation. Moreover, the number of litigants is relatively small, and your idea of hiring foreign lawyers is very good, so you won't have to pay more fees. Send some necessary evidence to the lawyer, including the power of attorney.
For risk agency, if you are prepared, the lawyer can accept it, yes, but you have to pay 20% agency fee.
If you don't believe him, you can remit the money to the account of his law firm.
If you call the police, it means that this case is a criminal case. It is more difficult for you to handle civil cases.
The police are not very helpful. Let them give you a decision not to file a case. Under normal circumstances, they are unwilling to do so. At this time, you can tell them that you want to sue them. Because citizens also have the right to sue government departments, this is an administrative case. There is no need to give evidence when prosecuting, which means that the burden of proof lies with the Public Security Bureau.