An insurgent accused of taking part in a bloody Baghdad church siege in October grabbed a policeman's gun mid-interrogation and led a prison mutiny that has left four Iraqi policemen and 10 insurgents dead.
Among the dead is the head of counter-terrorism for Baghdad's central Karrada district.
The incident came as security was tightened in Iraq where authorities fear reprisals after the death of Osama bin Laden last week in a US military operation in Pakistan.
