A 10-year-old boy has been charged with first-degree murder in the fatal shooting of his 7-month-old niece in St. Louis, Missouri. Court officials confirmed the charge Tuesday. The infant was pronounced dead at an area hospital after being rushed there following the incident on Friday.

According to court documents, the young boy allegedly retrieved a firearm stored under a mattress and shot the infant in the head. Another child, aged 7, was reportedly present in the home at the time of the shooting. Detectives determined the 10-year-old was responsible for the shooting, and he was taken into custody.

Investigators learned that the firearm belonged to the infant's father, identified as 19-year-old Ca’Marion Pawnell. Pawnell was arrested and subsequently charged with second-degree murder and multiple counts of child endangerment. Prosecutors allege that Pawnell endangered a child by allowing a firearm to be accessible to other children in the home, which resulted in the infant's death. He reportedly told police he stored the gun under the mattress.

The 10-year-old told investigators he was aware of the firearm's location and that it had been accessible to him for a significant period. He stated he had previously removed and handled the weapon. The boy is currently in the custody of the Missouri Children’s Division and is undergoing a psychiatric evaluation.

Under Missouri law, individuals under 12 years old cannot be tried as adults. Therefore, the 10-year-old will be processed through the Juvenile Division of the 22nd Judicial Circuit Court. No attorney information was immediately available for Pawnell, and it remains unclear if the 10-year-old has legal representation.