The woman accused in the killing of a 5-month-old boy back in early March pleaded not guilty to charges of murder Wednesday , court records show.

Barbara Kendrick was reportedly watching Cooper Dubovik when she became frustrated with him and threw the baby, who died from his injuries a short while later, police say.

The Jacksonville Sheriff's Office arrested Kendrick, who heads back to court May 16. She reportedly admitted to police she threw the child. Kendrick is the one who called 911.

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Kendrick faces charges of second-degree murder and aggravated child abuse.