The police video footage of the last moments of 6-year-old Jeremy Mardiss life shows deputy marshals firing a barrage of bullets at his fathers S.U.V. after a car chase on the dark streets of central Louisiana. It shows his father slumped over the open car window, injured and bleeding. Minutes later, the words of an officer can be heard: Theres a juvenile. The deputies had fired 18 times into the car, prosecutors say.