(Newser) – Police in South Carolina say a woman has been arrested for hitting her young son after he gave a Mother's Day card to his grandmother but not to her, reports the AP. A Spartanburg Police Department report says Shontrell Murphy is charged with cruelty to children for hitting her 6-year-old son on the head Thursday. Murphy's mother, Tracey Joanne Murphy, told police she saw her daughter hitting her son; when she asked why, the younger Murphy responded "because she could," reports WYFF. The boy's sister told police Shontrell Murphy ripped the card to pieces and hit the boy "hard." He was treated and released from a local hospital. Police say Shontrell Murphy has been released from the Spartanburg County Detention Center. It wasn't clear Sunday if she has an attorney. (Read more Mother's Day stories.)