The New Britain police department’s computer crime expert was stumped. The state police’s lab couldn’t help. Even the FBI didn’t have the answer. But Lt. James Wardwell kept searching, trying to find some way to infiltrate a stack of erased rewritable CDs he just knew once contained evidence. And eventually, thanks to a network of computer investigators, a Google search and some college kids blogging about how to restore their lost mp3s, Wardwell found a way to recover the data and developed a new technique in the process…