Is that an appropriate method to use to find the owner of an abandoned house?

Your tenants that have not paid you are either testing your ability as a landlord, were late payers with the former owner, or are saving up to move and abandon the premises.

Post an abandonment notice and a 2 days if it seems to be empty of people but not stuff. 

West of MLK blvd and route 40 (which is a part of west Baltimore) has a great deal of abandoned houses.

I would second what @John Warren said - I have looked at several half-done projects in my area and my first question is why are they abandoning this - aside from whatever the given reason is.

I guess i failed to mention Steve, the legal owner is deceased and the family members have abandoned the property. i'll most likely just keep an eye on it and check the records if the deed gets recorded.

But if it is obviously abandoned, say so in the letter.

In AZ I post a notice of abandonment which gives the tenant 5 days to make contact.

Newly abandoned?

I cant imagine that a house that has been abandoned for 10 years is worth anything near $300k in NOLA, no matter what the area is (and if it is, someone bought the tax liens hoping to do a tax foreclosure in the future).