(b)that there are reasonable grounds for believing that such person is engaged or is about to be engaged in the commission of an offence involving force or violence or an offence punishable under Chapter XII, XVI or XVII of the Indian Penal Code, or in the abatement of any such offence and when in the opinion of such officer witnesses are not willing to come forward to give evidence in public against such person by reason of apprehension on their part as regards the safety of their person or property, or