Factory reset. New owner sign on.

So typically when you factory reset something it resets everything but not fully so since Android has their new technology on their devices it makes it harder for thieves to steal it so if you could find the owner or talked to the people who you bought it from and see if they could give you the information to sign in one time so you can reset it to your needs but you need the old owners Pass key to get in and if you don't have that maybe if you could use Android apps shreddit or secure erabe with ishredder6 could halp to.. and if you could load a bunch of junk data on it like a fake account and downloading to big files and then factory resetting it again then when you reboot and create a new profile you would know the passcode and password I hope this helps you and I hope you'll be able to get it unlocked if not let me know and I will be happy to find a better solution for you