(CNN) The handgun was under a pillow in her grandmother's Detroit bedroom when the 5-year-old girl came upon it, police said Wednesday.

The girl, who was with two younger children about midnight, was playing with the weapon when it discharged, police said. She was fatally wounded, the latest casualty from shootings by children across the nation.

Her grandmother, who was cooking downstairs at the time of the shooting, was questioned by police and released, said Detroit Police Officer Jennifer Moreno. The investigation into the tragedy continues and no charges have been filed.

The victim, identified by CNN affiliate WXYZ as Mariah Davis , was pronounced dead on arrival at a Detroit hospital.

The other children, ages 1 and 3, were unhurt, police said.

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