Investigators are just beginning the lengthy process of determining why a business jet plummeted from the sky in Florida after encountering a thunderstorm and slammed into the ground with such force that it created a crater and shattered the plane.

The National Transportation Safety Board is leading the investigation into the crash that killed all nine people aboard the Bahamas-bound Learjet, and it will likely take more than a year to determine the cause.

Dramatic bystander videos combined with the the disturbing final radio transmissions as the pilots realize their fate will give investigators important clues.