Problem with previous owner's ID
Bought a second hand iPad and although I have deleted previous owner's ID, it comes up again when I try to Update Apps. This is the only time it happens. I have checked My Apple ID account and my address is the only one coming up as primary or any other address. I use my ID to download apps but when I try to update them, the previous owner's id comes up. Why? Why doesn't iTunes use the address saved in the account, ie, mine? Any help??? Thank you
iPad 2, iOS 8.4