A Fulton County mother and her boyfriend were sentenced to life plus 15 years in prison after being convicted Tuesday of killing the woman's 2-year-old son.

Jurors found Nikita Moore, 25, and Reginald Johnson, 27, guilty of murder, felony murder, aggravated assault, aggravated battery and cruelty to children in the 2010 death of Makel Moore-Thompkins.

According to prosecutors, Makel was unresponsive when the couple took him to South Fulton Hospital on Dec. 9, 2010. He was pronounced dead the following day.

Makel suffered from a fractured skull, bleeding on his brain and facial bruises, according to Yvette Jones, spokeswoman for Fulton District Attorney Paul Howard.

Jones said the defendants admitted to disciplining the child with a belt in an attempt to potty-train him, but denied any knowledge of how he sustained a head injury.

She said that according to the Medical Examiner's report, the injuries to the child's head occurred on multiple occasions, and Makel had more than 40 injuries both old and new throughout his body, "indicating a history of abuse."