[s4e23] | Roadkill

: Penelope Garcia helps the team by tracking the specific modifications made to the Unsub’s vehicle, which was customized with hand controls to allow him to drive despite his paralysis. Character Highlights

: This episode marks one of the early cases after Jennifer "JJ" Jareau returns from her maternity leave. [S4E23] Roadkill

The episode follows the Behavioral Analysis Unit (BAU) as they travel to , to investigate a series of vehicular homicides. The "Unsub" (unknown subject) uses a modified, heavy-duty truck as a weapon to run victims off the road or crush them. Key Plot Elements : Penelope Garcia helps the team by tracking

that may have inspired this "vehicular heat" storyline. The "Unsub" (unknown subject) uses a modified, heavy-duty

: David Rossi takes a lead role in empathizing with the suspect's physical limitations to help narrow down the profile. Notable Guest Stars Craig Sheffer : Portrays the Unsub, Mason Weaver. If you are looking for more specific details, The ending/climax of the episode.

: Revealed to be Mason Weaver , a man suffering from severe emotional trauma and a physical disability (paralysis from the waist down) caused by a car accident.