A tragic accident that killed a 15-year-old Marblehead girl has erupted into an emotional controversy as the victim’s grieving father is accusing prosecutors and cops of a coverup - an allegation vehemently denied by investigators.

“We feel very badly for the family but there is absolutely no coverup whatsoever,” Essex District Attorney Jonathan Blodgett said in response to allegations levied by the grieving father of Alessandra “Allie” Castner.