CBS

Season 9: Episode 19 - The Descent of Man

The Descent of Man: Nick's investigation of the attempted murder of a skydiver takes an interesting turn when Catherine finds that the skydiver was an accomplice in the mysterious double murder case of two Persian business partners that she has been investigating.  The business partners were killed simultaneously when a highly toxic substance was sprayed over their heads from an ultra-glider that was flown by the skydiver who was an unwilling accomplice to the real killers - the business partners' rivals in the Persian import business.  

Langston investigates the death of a self-proclaimed spiritual guru in the desert; after several dead ends, he discovers that a freak accident was the cause of death.