The episode you are referring to is Season 5, Episode 18, titled " Spark of Life ," which first aired on March 31, 2005. Episode Summary
William Petersen, Marg Helgenberger, George Eads, Gary Dourdan, Jorja Fox CSI Las Vegas 5x18
The "paper" or core plot of the episode involves a complex investigation into a fire at a construction site: The episode you are referring to is Season
: A burn victim is discovered in the middle of a desert fire. The team must determine if the fire was accidental or arson and if the victim was the target. titled " Spark of Life