Philadelphia property owner search help!

[Marc Izquierdo]

Does anyone know a good way to find property owners/landlords mailing addresses in Philadelphia? I've looked at a few sites including property.phila.gov but those addresses come up the same as the property's address. I know of a few properties that are not occupied so the owners mailing address should be different than the property's. I was able to find a site for Bucks county but I can't seem to find one for Philadelphia. Does anyone have any experience with this? I want to be sure I can find the information I need before driving for dollars. These government buildings don't seem to be open outside of a working Joe's hours so it's tough to just go and ask. I'm hoping there is a site for this. Thanks in advance.