any knowledge or capability he or she may have had and any stress or fear that may have been operating on his or her mind. 254 When defence of person partial defence to murder If a person accused of murder was defending himself or herself or another person against an unlawful attack when he or she did or omitted to do anything that is an essential element of the crime, he or she shall be guilty of culpable homicide if all the requirements for defence of person specified in section two hundred and fifty-three are satisfied in the case except that the means he or she used to avert the unlawful attack were not reasonable in all the circumstances. 255 Mistaken belief in relation to defence of person If a person genuinely and on reasonable grounds, but mistakenly, believes that he or she is defending himself or herself or another person against an unlawful attack, he or she shall be entitled to a complete or partial defence in terms of this Part to any criminal charge in all respects as if his or her belief were in fact correct. PART XIV DEFENCE OF PROPERTY 256 Interpretation in Part XIV of Chapter XIV In this Part “property” includes property of any description and any interest or right therein; “unlawful attack” means any unlawful conduct which endangers or infringes a person’s property. 257 Requirements for defence of property to be complete defence (1) Subject to this P art, the fact that a person accused of a crime was defending his or her or another person’s property against an unlawful attack when he or she did or omitted to do anything which is an essential element of the crime shall be a complete defence to the charge if (a) when he or she did or omitted to do the thing, the unlawful attack had commenced or was imminent; and (b) his or her conduct was necessary to avert the unlawful attack; and (c) the means he or she used to avert the unlawful attack were reasonable in all the circumstances; and (d) any harm or injury caused by his or her conduct (i) was caused to the attacker and not to any innocent third party; and (ii) was not grossly disproportionate to that liable to be caused by the unlawful attack. (2) In determining whether or not the requirements specified in subsection (1) have been satisfied in any case, a court shall take due account of the circumstances in which the accused found himself or herself, including any knowledge or capability he or she may have had and any stress or fear that may have been operating on his or her mind. (3) In determining whether or not any means used by a person to avert an unlawful attack were reasonable, or whether or not any harm or injury caused to an attacker was proportionate to that liable to be caused by an unlawful attack, a court shall have regard to the nature of the property which the person was trying to protect and its value to him or her. 258 Killing in defence of property A person accused of a crime involving the killing of another person shall not be entitled to rely upon a defence in terms of this Part unless (a) the accused resorted to killing after taking all other possible steps to protect the property concerned; and (b) the property concerned could not have been defended by any means except by killing; and (c) the property concerned was of vital importance to the accused; and (d) the accused believed on reasonable grounds that he or she would not receive adequate compensation for any destruction, damage or injury caused to the property concerned by the unlawful attack. 259 When defence of property partial defence to murder If a person accused of murder was defending his or her or another person’s property against an unlawful attack when he or she did or omitted to do anything that is an essential element of the crime, he or she shall be guilty of culpable homicide if all the requirements specified in sections two hundred and fifty-seven and two hundred and fifty-eight are satisfied in the case except that the means he or she used to avert the unlawful attack were not reasonable in all the circumstances.