An Alberta RCMP officer has pleaded guilty to assaulting a prisoner in a detachment cell.

Const. Desmond Sandboe admitted to beating a prisoner in a cell at the Lac La Biche detachment on Sept. 13, 2009.

A videotape showing Sandboe assaulting the prisoner was shown in court Friday.

In a statement, Supt. Joe Loran, acting commanding officer of K Division, said the incident is "appalling."

Loran said Sandboe, a nine-year veteran of the RCMP, has violated the public's trust and has done a great disservice to other RCMP members.

Loran has recommended Sandboe be suspended without pay. Sandboe will be sentenced on Jan. 27.

An internal investigation is underway and will be completed after the criminal court process has ended.

Disciplinary actions include a range of measures up to and including dismissal.