What's the best way to find contact info for another owner?

[Allen L.]

I just bought a half duplex and want to waterproof the basement. However, the other side is abandoned and unsecured. The basement of the other half is completely molded and needs gutted. I can't properly waterproof my basement without having theirs waterproofed as well. I want to reach out to the other owner and purchase that side so I can resolve this issue. What's the best way to find most up to date contact information of the owner? County records show it as her primary residence but she is obviously not living there anymore.