How to find an off market property owner

[Christa Coore-Powell]

Hello!! I went to see a distressed property to BRRR and there was a great, empty also distressed property across the street. I found the name of the owner on the county tax assessor site but I can't seem to find a mailing address. Any suggestions on finding the address AND if you've written a letter to an owner of an off list what did you say? THANK YOU!!