"I'm sorry, Mom. I shot Corbin."

In what police have said was a tragic accident, the 5-year-old had gotten hold of his grandfather’s .22 caliber Magnum revolver and fired a shot that struck Corbin in the head, mortally wounding him.

As she grieves for her baby and worries about the future of her eldest son, whose name is being withheld by NBC News, Wiederholt said her loss should be a warning to others to protect children from firearms.

She said she had no idea that her father, William Porter, kept a loaded pistol in the Elmo home she and the children were visiting.

“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.”