Answer:
This question has been raised scores of times in Bankers' Threads, and the answer hasn't changed. Although you certainly may request your customer's cooperation in the investigation, and can suggest the filing of a report, you cannot make the police report a condition precedent to your investigation or to the granting of provisional credit.
Here's a LINK to just one of the many threads on this question.
First published on BankersOnline.com 3/7/05