An 8-year-old boy has become the youngest person in Alabama to be charged with murder for allegedly beating a 1-year-old baby girl to death.

Police say the incident occurred on Oct. 10, when the mother of the victim, 26-year-old Katerra Lewis, and her roommate, a mother of five, left their children home alone to go nightclubbing in Birmingham, reports ABC 7 Chicago.

The mothers left their home around 11 p.m. that night and returned around 2 a.m. However, Lewis didn't discover that her daughter Kelci Lewis was injured until later that morning.

Police say they received a phone call about an unresponsive toddler at about 10:30 a.m.

After speaking with a 6-year-old child, who was also left alone with no supervision, police learned that the 8-year-old became extremely agitated when Kelci did not stop crying. He then "viciously attacked" the baby, Birmingham police said, according to CNN.

Officials say the 6-year-old's story was consistent with the toddler's injuries, which included severe head trauma and "major internal organ damage," police said in a statement.

On Tuesday, police announced the 8-year-old will face murder charges, while Lewis is being charged with manslaughter for her role in the death of her daughter.

"This is by far one of the saddest cases that I have witnessed and been a part of since I became a police officer," Lt. Sean Edwards of the Birmingham Police Department said Tuesday. "This type of irresponsibility on behalf of a parent is totally unacceptable."

The 8-year-old boy, who was the oldest of the six children left alone, has since been placed in the care of Alabama's child welfare agency, the Department of Human Resources. Although his mother has not been charged, her other four children, ages 2 to 6, have also been removed from the home.

"The sad part is you had an adult mother here who had the audacity to leave her 1-year-old in the custody of several other children at the house and none of those kids were over the age of 8," Edwards said. "I think her punishment is going to be something she'll have to live with the rest of her life, her actions that night, choosing the club over taking care of her 1-year-old."