Off the bat, I can tell you that this property does have liens. Sure it may have 100 equity, per mortgage obligations, but since you mentioned problems with the city (weed or tall grass liens) you might consider checking it out. Consider the following;
(1) Go to county records & verify the lien issue of the property (it'd be great if you get the parcel # off the owner, and if can't the address should suffice)
(2) Talk to city inspector & request records for the last 3 years, if available, verify amounts wed, if any. Should you'd be sure that you want to deal with the property in question
NOTE: A warm smile and a joke will yield heaps of help with city & county employees. The one I have used, for example, with the criminal court clerk -- "Hey, did you hear about the scandalous traffic case? Apparently, a defendant was trying to make a federal case off a parking ticket that he got at the beach down & Broward. Finally the judge had enough & asked the defendant, 'Sir, did you NOT see a sign?' And the guy replied, 'Sure I saw a sign, your honor. It said FINE FOR PARKING'."
(3) Should you go ahead wit the deal, get QC from owner by requesting him/her to FedEx the original deed as without it a LP will have to draft a new one, which will cos you around $300. NO MATTER WHAT REMEMBER THAT ATTORNEYS TOO ARE BUSINESS PEOPLE SO NEGOTIATE PRICE OF ANY & ALL SERVICES
(4) Get the property inspected & consider possible expenses for the next 12 months should you decide to flip it or rent it out. NOTE, that roofing could cost up to $5,000, and god knows how much would you need to pay for water heater, A/C and other.
Whatever you decide, I do wish you the best of luck.
ralph