ATLANTA — An 8-year-old boy has been charged with murder in Birmingham, Ala., where the police said Tuesday that he had “viciously attacked” a toddler whose mother had left children alone while she visited one of the city’s nightclubs.

The authorities announced their intention to prosecute the boy, who was not identified, nearly a month after the death of 1-year-old Kelci Lewis. The child was found unresponsive on Oct. 11, and a police spokesman said Tuesday that investigators believed the older boy had become violent because the toddler would not stop crying.

“The 8-year-old just recklessly, viciously dealt with the 1-year-old,” the spokesman, Lt. Sean Edwards, said at a news conference on Tuesday, one day after the girl’s mother surrendered to the authorities and was charged with manslaughter.

Lieutenant Edwards said that the mother, Katerra M. Lewis, and a friend had left the home where they were staying late on Oct. 10. Six children, none of them older than 8, remained at the home, and while Ms. Lewis was away, the lieutenant said, her daughter began to cry.