I've sold several war zone properties in Memphis over the years and surprisingly they usually turned out to be great rentals because you can get them super cheap and put a minimum amount of work in them. If you can find a good tenant, like an elderly person on a fixed income, you'll get your rent like clock work and make great returns.
I know a guy in St. Louis who invest in war zones too, but he buys the house and sells them with owner financing to owner occupants with out doing any kind of work to them at all. He'll buy something for say $3k and owner finance it to an occupant for say $6k, but the new owner has to do all the work to it go get it livable.
I tried to sell one in a war zone in St. Louis too, to an owner occupant. She loved the house and we agreed to meet the following Monday to sign the papers. As we were both walking to our cars, 3 gun shoots rang out. Needless to say, she did not proceed with the purchase.