How to get rid of a passcode on a iphone 4s that is not yours?

A few days ago I found a Iphone 4s in my school gym locker but it has a passcode. When I try to restore it with itunes it says that Itunes can't connect to the iphone because it is locked with a passcode and i need type the passcode in.

I think you should to restore the iPhone 4S to its owner, not to possess yourself of it via "Hack" the passcode…

You need to give that phone back to its rightful owner.

Whether you've forgotten the password to your Apple iPhone 4 or somehow a lock has appeared on the center of the screen and you can't get past it,
http://www.technipages.com/iphone-4-forgot-password.html

Turn the phone into a teacher or principle. You did not find aElse'se, you stole a phone. Put it back or turn it in.