Monroe County sheriff's deputies were on a stakeout to catch an arsonist.
Detective Thomas Redmond says he watched as the 17-year-old boy walked from his home to Redmond's unmarked car.
Deputies say the teen unscrewed the gas cap and started siphoning fuel.
He tried to make a run for it, but the young man was arrested.
Investigators say he later admitted to setting a total of five fires.
