A baby has been killed after being shot in the head at the hands of his five-year-old brother, who was playing with a magnum revolver.
Mother Alexis Widerhol, 26, had put her nine-month-old down for a nap and headed to the kitchen when she heard a loud noise that sounded like a gunshot.
Ms Widerhol told NBC she rushed to check what the noise was, her son said: "I'm sorry, Mum. I shot Corbin."
"I walked in and there was my baby, lying there, bleeding," she said.
Ms Widerholt told 911 her son had shot her baby in the head with a paintball gun having seen her kids playing with one in the living room, but a real firearm was found at the scene, Sheriff White said.
The nine-month-old was rushed to hospital in Kansas City in the US but was pronounced dead on arrival.
The tragic incident occurred after the baby's brother found his grandfather's .22-calibre Magnum revolver "just lying out", police said.
"Little kids are curious. It was in the headboard of the bed, and he found it," Sheriff White said.
Ms Widerhol told NBC she had no idea the gun was in the house.
"I didn't know it was there until I turned around and saw it laying on the bed," she said.
"I don't know why someone would have a loaded gun in the house while kids were around."
Ms Widerhol's father, William Porter, said he has always kept the gun in his room.
"I told the boys they weren't supposed to be in my bedroom where I keep the gun cabinet and they knew it — but like I said, boys will be boys," he told NBC.
Police said there is no reason to believe the shooting was anything other than an accident.
"We are big supporters of firearms around here," Sheriff White told KETV in the US.
"We have a lot of people that own weapons... Most people are very safe with them, and this is one of those cases where everything went together in the wrong way."
As the family comes to terms with the tragedy, Ms Widerhol said her five-year-old still has not processed what happened. She does not know why he fired the gun, except that "maybe he thought it was something off a TV show".
The incident is the latest in a series of shootings involving children in America in recent months.
In January, a four-year-old girl killed her cousin in Detroit while playing with a gun found under a bed. In August, a nine-year-old girl accidentally killed a shooting instructor and in December a two-year-old fatally shot his mother at a supermarket in Idaho after finding a gun in her purse.