Used MacBook "Find my"

Help. I just bought a used MacBook and when I went to set it up, after putting my Apple ID, I got to the "find my mac" screen and it still says the previous owners Apple ID will be used to remote lock and erase it. Reading every thing online says the MacBook could be stolen, or lost, or the previous owner sold it without removing their Apple ID from the "find my mac" prior to selling it. Of course, as soon as I tell the seller what I found, he admits he isn't the original owner, and the computer was sold to him from someone else. First, I can't reach the person with the Apple ID so there is no way to ask them to remove it. Can I remove it completely? I've read about resetting the NVRAM, but can the previous owner still remote lock and erase it?

Or, do I even bother and just return it? Help please.