04E10 - Built for Speed

The team investigate the death of a street racer, Alberto Santana, who died when his car exploded during a race. He has a criminal record and served time for auto theft. Fortunately, Giovanni the mechanic was there and recorded the race. What they can't see from the video is his opponent who goes by the name of Rayo. Maura and a handsome bomb squad officer find evidence of a bomb in the remains of the car. They also find a microSD card with images of the driver and the explosion from inside the car - it also shows that Lt. Martinez was there but hasn't offered any assistance in the investigation. A common link between the various suspects leads them to the killer.