The trick is getting a warrant so that the ISP will turn over the DHCP logs on which modem had that particular IP address at the time and then tracing that back to the subscriber account. Then you have to get another warrant for the police to search the property for your laptop. You'll have to find someone interested enough to do all of that work for you. Good luck man.

We use Alfresco Enterprise and it should do exactly what you want. The free Community version is just as good and several of the engineers actively participate in the user forums on their website.

Nothing is more enjoyable to your users than machines named 010010010010.domain.local