BAYONET POINT — A 21-year-old woman was arrested Monday after deputies said she struck her 66-year-old grandmother in the head with a hammer.

Skye Stamper of Bayonet Point faces a charge of aggravated battery on a person older than 65, according to the Pasco County Sheriff's Office.

Here's how the agency described the incident:

The grandmother, Rebecca Harris, said she was sitting on her back porch at about 8 p.m. Saturday when Stamper struck her in the back of the head with a hammer, according to the Sheriff's Office.

The blow left an inch-long cut on Harris' head, deputies said. Then Stamper hit her grandmother twice more in the back of the head, deputies said, bruising her. A witness saw the attack, according to the Sheriff's Office.

Deputies were sent to Harris home on Elkton Avenue at about 1:15 p.m. on Monday. That's when Harris reported that her granddaughter had assaulted her two days prior. Stamper's arrest report does not give a reason as to why the assault took place.

Stamper was being held Tuesday without bail in the Pasco County jail.