The offices couldn’t be more generic. The building is nondescript. There’s a sign outside the door, but they’re planning to take it down. But inside the Cyber Crimes Center in Fairfax, Va., investigators are cracking the most sensational, gut-wrenching criminal cases involving the Internet. As a result, thousands of people around the world are being arrested; many are going to prison. The center is a state-of-the-art forensic computer lab run by the U.S. Immigration and Customs Enforcement agency to help investigate domestic and foreign crime conducted on or made possible by the Internet…