Horatio and Frank interrogate Russel Miller, who finally confesses to murdering the valet/pimp, being seen by a driver whom he chases down and murders, then hides the murdered pimp/valet in that trunk. Then Horatio says "Frank, read him his rights." Everything said in interrogation prior to reading him his rights would be inadmissible in court, so there would really be nothing left for which they could arrest him.
After the car crash, one of the crime techs points to a traffic camera near a set of traffic lights. But the red light was flashing.