The cell in which a sexual incident occurred is monitored by guards via closed-circuit TV. (CBC)

An investigation by the RCMP Public Complaints Commission has found that three officers accused of watching two female inmates have sex in a jail cell without intervening demonstrated a lack of professionalism.

The commission said Wednesday that, while the RCMP investigation of the incident was thorough, the force failed to recognize an issue that could lead to a perception of bias when the force investigates its own members.

The commission made four recommendations, including that the RCMP consider amending its policy in connection to when an investigation should be turned over to an external agency.

The Elizabeth Fry Society filed the complaint after the August 2010 incident came to light.

The women -- who had been arrested separately and were both clearly intoxicated -- were being held in the drunk tank when the officers and a guard allegedly watched them have sex via closed circuit TV.

Cpl. Kenneth Brown, Const. Evan Elgee, Const. Stephen Zaharia and guard David Tompkins still face breach of trust charges in the case.