Four prison killers, who were last May sentenced to life in jail for murdering a fellow Jaw Prison inmate in cold blood, were found guilty, with another cellmate, of beating up three prisoners and breaking the jaw of one of them.The badly injured inmate, who lost five teeth in the attack, has been left with permanent injuries, evaluated as a ‘10 per cent disability’, after he suffered ‘multiple fractures to the jaw and face’ at their hands .