How can I remove icloud or turn off find my iPhone without password
Here is what happened:
I was charging my iPhone 6 on my laptop and my brother asked to use it so I let him. He had an iPod 4th generation and I didn't think much of it. Later when he wasn't home I checked my iPhone to see if it was full and I noticed everything was different, I was still able to log in with my normal 4 digit password but there was a different icloud account signed in I can see the whole email but I don't know the password. I asked my brother and he said he found the iPod and restored the backup on my iPhone. Now it has some icloud that is not mine and I don't know what to do. My iPhone is running ios 8.1.3. I need to deactivate find my iPhone to be able to restore my backup but I don't know the password.
iPhone 6, iOS 8.1.3