We had a break in and my 2011 iMac running ML was stolen. It is on my list of devices on Find my Phone on iCloud.com but as I understand it, locking it with that will only put a 4 digit lock code on it. Apple says it is a firmware lock and no one is getting in. But it can't be erased once I choose that option. Unfortunately the machine has a password to the main account and while there may or may not be a guest account active, I'm not sure they'll even get it on the internet to perform a remote lock or wipe. It has yet to appear online in my list of devices. Any suggestions on what I should do. Thanks.