GRAND RAPIDS, Mich. — A former Michigan Department of Corrections employee is facing charges after investigators allege she intentionally opened an inmate’s cell door, allowing the prisoner to attack another corrections officer at a state prison in Michigan’s Upper Peninsula.

According to Michigan State Police investigators, Shelby Pennock, 44, was charged with assault of a prison employee following a March 28 incident at the Baraga Correctional Facility.

Pennock was arraigned July 14, and a judge set her bond at $500, according to court records according to WLNS.

Investigators allege Pennock and another corrections officer were working together in a cell block when she opened an inmate’s cell door, knowing the action would result in an assault against the other officer.

State police said the incarcerated individual immediately left the cell and attacked the corrections officer.

Investigators said the officer was placed in a headlock and repeatedly struck in the head and upper body during the assault.

The officer suffered injuries that were not considered life-threatening, according to Michigan State Police.

Corrections staff eventually regained control of the situation and stopped the attack.

Troopers said Pennock was also assaulted by the inmate during the incident and suffered injuries.

The investigation was conducted by Michigan State Police, which later presented findings to the prosecutor’s office. Prosecutors authorized the charge against Pennock, who is no longer employed by the Michigan Department of Corrections.

The inmate involved in the attack is also facing felony charges, though Michigan State Police said the individual had not yet been arraigned as of Monday.

Pennock is scheduled to appear in court August 11 for a probable cause conference.

The allegations remain unproven. Pennock is presumed innocent unless and until proven guilty in court.