4-year-old shoots mother after expressing curiosity about guns

A 23-year-old mother from Gig Harbor, Washington was unintentionally shot in the back by her 4-year-old son. The mother was talking on the phone with her back to her son when she was shot. She was shot on her left side with a 12-gauge shotgun.
The boy found the unloaded shotgun on the bed. "All the kid did was drop the shell in the chamber, touch the bolt release and pull the trigger," police said. "He had probably seen his dad do it a hundred times."
Before the incident the boy's father gave the boy a shotgun cartridge so he could learn to handle it. According to police, "The boy had expressed curiosity about firearms and his father provided him with one shotgun ammunition round."
Ohh shoot.