Thank you everybody for your advice!
I did hire an inspector, he did a good job but the structural issues were not discovered until we demolished everything to the studs and determined that the building's walls and floors are in dismal shape.
I am rehabbing the building with permits--you name it: architectural plans, engineer's plans, electric, plumbing, roof, etc. But it's going to cost a lot.
I realize I took a risk buying this property, and I have learned a lot from this experience. Still, I wanted to get an idea what my rights & position are in this situation.