Looking for abandoned/absentee owned properties

[John Cha]

I'm a Chicagoland Realtor helping out a friend buy rehab and hold something that he can qualify for a loan without an active credit score. He calls himself the ghost and I reckon vacant, beat up homes would be viable for a private lender to work with him provided he has a cosigner/partners. What's the best way to locate vacant properties online (off market or active doesnt matter)? It's clear how to get a hold of the owner through public records once I spot the actual property, but how do I find them in the first place? Ive used the MLS and homesnap and can't seem to narrow down my search for this criteria.