Use a computer at a TW@ Internet Cafe to access the Liberty City Police Department site at "www.libertycitypolice.com". Click the "Database" tab at the bottom of the home page to get information on every character, including Roman and Niko.
Go to the Liberty Tree website's main page and click the link to the LCPD website. There are a few interesting things, like the Threat Level, but aside from that it appears bare. However, when you go to the bottom and look at the copyright information, the word "Database" is a small hidden link that leads to a large profile list of criminals. Of special importance are Lola Del Rio, the hooker featured on the box art, Eddie Low (the No-Name Killer), and Niko Bellic, among others.