Finding out who owns a property

[Jesse Frageman]

I recently noticed two small multifamily properties in my neighborhood that look neglected. When I looked up who owns the properties on my county's tax portal, the county shows the owners' mailing address as the address of each respective property. 

How do I know if these properties are owned by an out-of-state owner? By the way they look, they don't look like they are owner-occupied and being kept up.