Florida Man Believed Dead After Falling into Sinkhole A lpt out of florida is a reminder to millions of americans there's a strange and dangerous vulnerability under ground, sink holes. A man was in his bedroom, the earth opened up beneath the house and he fell in. Matt gutman shows us the science of what happened in florida and how to know what's under your house. Reporter: Horror struck the house on faith way drive just before midnight. The house fell through. Reporter: These tapes reveal the terror. A sink hole some 30 feet across and 100 feet deep opened up directly beneath jeff bush's bedro bedroom. His brother tried desperately to save him. I jumped in the hole, tried to dig him out. I couldn't find him. I started digging and digging. The cops showed up and told me, the floor is still falling in. Reporter: Jeremy was rescued by police, but his brother is believed dead. The house condemned. The bush family said they had no idea they lived under a geological time bomb. This part of florida is known as sink hole alley. Look at these, all reported sink holes in florida since 1954. Seven other states are classified as sink hole prone, covering up to 40% of the country. Sink holes form when limestone is eaten away by water, but the land above it stays in tact until it gives way. It burns through the rock. Reporter: The result, sink holes like this growing to the size of a football field in the single day in 1981. This sink hole in houston, devouring a tractor. Reporter: Are there ways to detect whether you have a sink hole? Very expensive and difficult to do. And it might only be good for as long as the test is done. Reporter: Experts say it's rare to be hurt by a sink hole, but there are things to do to protect your family and house. Look at the walls, are they cracking? Are the doors harder to open and close. Fences and vegetation, if those things have moved, you might want to get your house looked at.