In the original series CSI: Crime Scene Investigation (often called CSI: Las Vegas ), refers to the 19th episode of the 5th season , not the 4th episode of the 4th season.
Catherine and Warrick investigate a hit-and-run involving a stolen Hummer H2. CSI Las Vegas 4x4
This episode is unique because it features that eventually become interconnected through a single event. Episode Overview: "4x4" (S5E19) Original Air Date: April 14, 2005. In the original series CSI: Crime Scene Investigation
The episode follows four different crime scenes investigated by different members of the team simultaneously. Episode Overview: "4x4" (S5E19) Original Air Date: April
A 12-year-old boy is found dead on a street bench.
While the cases initially seem unrelated, they all converge on a single vehicular accident involving a stolen Hummer. The Four Intertwined Cases
If you were specifically looking for the 4th episode of Season 4, it is titled "Feeling the Heat" . It follows three heat-related cases during a Las Vegas heat wave, including a baby left in a hot car and a drowning at a lake.