A Delaware mother has been arrested on assault charges when police discovered that she beat her 9-year-old son with an extension cord for taking a check from her checkbook so that he could buy a book from his school’s book fair.

Serena Wardlaw, 42, of Briarcliff Drive in the New Castle, Del. community of Overview Gardens was arrested on four counts of assault and five counts of endangering the welfare of a child, police say.

Police were called to the 9-year-old boy’s elementary school after a school nurse discovered wounds on the boy’s arms, police say.

An investigation revealed that Wardlaw was enraged when she found out that her son took one of her checks and she beat him with an extension cord all over his body, police say.