Help getting police check from PSB in wuchan china as part of requirement (see below)

I'm a Canadian Citzen who spent two years teaching in wuchan. I married an American Girl and have gone through the complete green card process and the only requirement left is to get a criminial record check from PSB in wuhan. Can you advise me as to where and how to start. Is there a firm we can hire or someone you can put us in touch with.