Mother allowed fatal beating of son over piece of birthday cake

A US woman has pleaded guilty to first-degree child abuse over the beating death of her nine-year-old son over a missing piece of birthday cake.

Prosecutors agreed to drop a second-degree murder charge and seek a sentence of no more than 20 years for Oriana Garcia, who appeared in a courtroom in Hagerstown, Maryland.

The 27-year-old's son Jack was handcuffed to a chair by Garcia's brother and pummelled by her boyfriend, who suspected Jack of eating cake meant for his two-year-old daughter.

Police said Garcia allowed the abuse and sent away an ambulance as Jack lay dying.

The boyfriend, Robert Wilson, is serving 30 years for second-degree murder.

Jacob Barajas is awaiting sentencing for first-degree child abuse.

- AP