The devastated stepdad of an 11-year-old boy shot dead in a road-rage attack screamed “my kid is dead” to cops and collapsed onto a Nevada freeway — as the alleged gunman calmly copped to the killing and surrendered, newly released police bodycam footage shows. The chilling video, released by the Las Vegas Metropolitan Police Department, shows the boy’s stepfather, Valente Ayala, wailing in anguish at a stunned officer that his stepson, Brandon Dominguez, lay dead in the backseat of his car after a heated clash on a Las Vegas-area freeway on Nov. 15.