A Knox County, Tennessee, inmate has been charged with the attempted first-degree murder of a corrections officer.

Talanda Yarbrough, age 21, of Knoxville, attacked the officer as she was being led out of her cell for recreation time yesterday at the Roger D. Wilson Detention Facility. Yarbrough punched Officer Tiffany Brackett in the face and then grabbed her ponytail and pulled her head down. During the attack, Yarbrough grabbed the officer’s pen from her uniform shirt sleeve and began stabbing at her head and arms. Officer Brackett attempted several maneuvers to stop the attack, but was unsuccessful. Security arrived and took the inmate into custody.

Officer Brackett was taken to Fort Sanders Hospital, where she received seven staples to the back of her head and was treated for other injuries.

Yarbrough was initially in jail for aggravated assault. She is accused of beating her grandmother over a cell phone.