(Newser) – A 3-day-old boy was fatally mauled by a pet dog as his parents watched helplessly in their San Diego home, the AP reports. Sgt. Tu Nguyen said the parents were in bed watching TV with their newborn son and pit bull-mix Thursday night when the mother coughed, startling the dog. Nguyen said the dog reacted by biting the baby, resulting in a traumatic injury. He said the parents pulled the animal off and took their only child to the hospital, where he was pronounced dead. Nguyen called it a "tragic accident." The San Diego Union-Tribune reports animal control officers took the 2-year-old dog into custody. (Read more animal attack stories.)