Google likely wanted to keep this quiet, but if they'd turned this over to the FBI, I'm sure there would have been no trouble finding laws he'd broken.
If I break into google and poop on the floor of their server room, I can be arrested, but if one of their sysadmins gets in with their key and then poops on the floor of the server room, they can only be fired.
http://www.justice.gov/criminal/cybercrime/ECPA2701_2712.htm
Even if it's not, I maintain that if you've done something that seems like it might be illegal, they can usually find something to charge you with.