A three-year-old girl accidentally shot and killed herself after mistaking a handgun for a Nintendo Wii video game controller.

Cheyenne Alexis McKeehan shot herself in the chest with a .380 calibre pistol after finding her stepfather’s gun lying on a table in the living room of the family home in Norene, Tennessee.

Police believe she mixed up the semi-automatic with a gun controller for the Nintendo Wii, which looks similar and which she had learned how to use from playing on the games system.

Douglas Cronberger, 32, the gun’s owner, said he had forgotten he had left the gun out after he took it from its cabinet when he went to investigate a suspected prowler on Sunday evening.

He had already gone to bed, but Tina Ann Cronberger, the child’s mother, was sitting only a few feet away using a computer when the accident happened, while her three-month-old brother was playing nearby.

Prosecutors have made no decision on whether any charges will be filed, but Terry Ashe, the sheriff of Wilson County, described the case as a “terrible tragedy investigation”.

Displaying the gun alongside the Wii controller, he said: “You can see by the comparison of the toy weapon and the real weapon that there’s little chance a three-year-old would differentiate between the two.

“‘If you have a live handgun with a toy that looks the same – for parents some bells and whistles need to go off.”