Who do I contact about this house?

[Keith Vincent]

More specifically tax liens in NYC. I came across this distressed property in my town. Its currently vacant, windows and doors are boarded up. I looked up the transaction history and noticed the tax lien sale back in 2012 which was discharged a few months later (the document says it was paid). My question is who do I contact in order to purchase this property? Do I call the lien servicer, the mortgage bank or the owner?