What everybody is suggesting that your insurance company should handle the case and police report should be sufficient. Your insurance company should handle the case. This is normally done through most of the insurance company. Looks like it is not your situation and you insurance company is asking you more. Consult with your insurance company and get the detail what is expected from you and what is expected from them. I guess you have no choice but to follow the instruction from your company (which is not the normal case)

BTW what is your insurance company name?