IPad locked to owner

You need the credentials for the iCloud account that was used to lock it.

Only the owner of that account can remove the activation lock.

If you purchased it used, talk to whoever you got it from. If they can't or won't remove the lock, get your money back.

If you can't do that, turn it over to the police. it's probably stolen

Then use the iCloud account you were signed into on that device.

What's the problem, exactly?