ipad stolen
My son's ipad has been stolen at his school a few days ago. He has a passcode and find my Ipad was enabled. I set it on lost mode with my number and message, but It has been offline since the day it was missing and cannot be located. So now I'm wondering, whoever (probably another student) has his ipad cannot get in to his ipad cause he/she doesnt know the passcode, and connect it to the internet. I did "erase my ipad" but then it says it will be erased when it connects to the internet, which is not happening. Is that ipad useless for them now? Do i have any chance locating it, or at least block it and make it useless if they somehow figure it out?
iPad Mini, iOS 8.3