RELATED VIDEO CNN's Brian Cabell gets down and dirty in North Carolina caves Windows Media 28K 80K

TUXEDO, North Carolina (CNN) -- It's been a year since the bombing at an Alabama women's clinic and more than two years since the Olympic Park bombing in Atlanta, and federal authorities are still searching the wilderness of western North Carolina for accused bomber Eric Robert Rudolph.

One of the tools in their arsenal is cave expert Darren Free, who's using his spelunking skills to track one of the nation's most wanted fugitives.

Correspondent Brian Cabell goes underground.