Security footage shows the ground subsiding, sinking cars etc immediately prior to the collapse - so the building evidently wasn't anchored properly, and when a sink-hole happened, down she went. It's Florida, sink-holes are a regular event. Either cores taken to determine ABP weren't of a sufficient depth to determine what was really bedrock and what was merely a big-a$$ "floater" (a boulder with softer material underneath it), or the builder skimped on the piers, not drilling them to sufficient depth. Or both.
I suppose that we will eventually find out the cause of this tragedy, but watching it on the news reminded me of 9/11 and the Towers pancaking down. What an absolutely horrible way to die.