The saga continues regarding South High School in Knoxville. The current owner bought it from the city at auction, paid about $120,000 for the property in 2008, but is not maintaining it. Take a look at the News Sentinel article here. Evidently, the lot has become overgrown and the city feels that the owner is demolishing the building by neglect. The owner has until August 13, 2012 to appeal the unfit for habitation determination, or the city will board it up.
These types of cases are difficult. My feeling is that in terms of historic preservation, the city itself has the best chance of saving an older structure. Usually it has more money, it is exempt from zoning regulations, and it doesn't have to market the property to private users. However, once the property is sold to a private owner, there is always a risk that money will run short, zoning regs certainly apply, and the private owner must market to the vagaries of market purchasers. This case will be interesting to follow.