Duplex with 600K

[Nat C.]

I've been watching a property on the MLS for the past 2 months.

It's a duplex in an A grade neighborhood for 300K, which is well below similar listings. Redfin estimate prices its value at 350K.
The MLS listing states there are liens and violations.
Listing agent told me there is a 600k in fines for work without permits.
City will not give me any further info as I'm not the owner.
If I have it under contract I can get the owners written permission to converse with the city. I know people who negotiated a 1 million dollar lien down to $1000

It's been in the market for a long time and it's a short sale.

I am thinking of submitting a low ball offer of 220K.

Is this too low ball or justifiable for the 600K lien?