The parents said they made the decision because it could "do some good."
The Atlantic County Prosecutor's Office took over the case of Brandon Holt's death because the parents of the 4-year-old have relatives who worked in law enforcement in Ocean County.
Police said the boys were playing Monday when the 4-year-old got a loaded .22-caliber rifle from his family's Toms River home and accidentally shot Holt in the head.
Investigators want to know how the younger boy got the gun.
Meanwhile, Holt's funeral will take place Saturday.