I want to get the owner's number

I have an iPhone that they gave me that was lost in a restaurant they lasted for weeks they didn't look for it they decided to bring it to my country I'm from

Latin America iPhone is not reported as stolen or anything

but ask for a previous icloud account I would like to contact the owner to see if you could buy the device and they can unlock the iphone or deborveronly but I want to do something with it thank you good