How can I get collection agency to produce evidence of creditor claim?

If the debt is from after the date of your bankruptcy then they have the right to go after you for that amount. Without a police report, the card is your responsability. With credit cards they may not have the signature. However this doesnt keep them from placing it on your credit bureau, and if they bought the debt then they may be able to get around some of the Fair debt laws. I suggest you let your attorney handle this one