Ask HN: Getting back at a scammer with scammer's phone number and bank details?

My flatmate is an eBay trading assistant here in London in the UK. She doesn't get much work from it, but from time to time it helps her make a bit of extra money which helps as she is currently out of work.

A guy called her the other day with a sob story about having to sell his Macbook because he was behind on his rent and being threatened with eviction. She made the mistake of allowing him to send the package directly to the customer, providing a tracking number as proof of postage and due to being a little too trusting, transferred the payment to him on receipt of the tracking number.

Obviously she should have taken possession of the goods directly and then mailed the goods to the customer herself. Nevertheless, she is now extremely broke, being threatened by the customer, and doesn't have any money of her own to reimburse them with.

She has the scammer's phone number and bank account details. She has filed a report with the police who told her that the fraud investigation unit may or may not bother to investigate it. The bank is not being helpful either.

Given a phone number and bank account details, is there anything creative she could do (or have someone else do) to figure out who the scammer is and potentially get the money back?