Owner of this phone is know where to be found. How can I use this phone?
Previous owner can not be found how can I activate this iPhone 4?
iPhone 4, iOS 8.1.1
You cannot. And, Apple will not assist you in this either. Take it back where you bought it and ask for your money back. You will not be able to activate the device without the previous owner's information. The device is useless to you.