Find the attacker behind a proxy network

We are being targeted by an online attacker who sends hundreds of requests to our server every minute. We are not sure if this is a DDOS attack or is it for scraping/data theft or otherwise, but we have a large list of IP addresses, with associated URL's requested, with timestamps. The IP's are (as expected) proxy servers all around the world. We need someone who can track down this attacker and provide us with a (source) IP address (or any other information) regarding this attacker, so we can press legal (or informal) action.

Let us know if you can do this.