I have a iPhone with Activation lock but don't know who the owner is? What do I do?

Only using the credentials that were used to activate that iphone can bypass the activation lock.

Neither we, nor Apple can help you about that problem.

Regards

Giulio

You return it to whoever you got it from or turn it over to the police.

You can't use it. It doesn't belong to you.

There is no way to bypass the activation lock.