In the case of State v. Faulkner, 301 Md. 482, 485, 483 A.2d 759, 761 (1984), the Court of Appeals of Maryland summarized those principles, and stated that a homicide, other than felony murder, is justified on the ground of self-defense if the following criteria are satisfied:
(1) The accused must have had reasonable grounds to believe himself in apparent imminent or immediate danger of death or serious bodily harm from his assailant or potential assailant;
(2) The accused must have in fact believed himself in this danger;
(3) The accused claiming the right of self defense must not have been the aggressor or provoked the conflict;
(4) The force used must have not been unreasonable and excessive, that is, the force must not have been more force than the exigency demanded.
See also Roach v. State, 358 Md. 418, 429-30, 749 A.2d 787, 793 (2000).
A person does not have to retreat if it would not be safe for the person to do so. "If the peril of the defendant was imminent, he did not have to retreat but had a right to stand his ground and to defend and protect himself." Bruce v. State, supra, 218 Md. at 97, 145 A.2d at 433.
The duty to retreat also does not apply if one is attacked in one's own home. "[A] man faced with the danger of an attack upon his dwelling need not retreat from his home to escape the danger, but instead may stand his ground and, if necessary to repel the attack, may kill the attacker." Crawford v. State, 231 Md. 354, 361, 190 A.2d 538, 541 (1963). The Court of Appeals said in Crawford, a case in which the defendant fatally shot a younger man who was attempting to break into his home to beat and rob him:
"A man is not bound to retreat from his house. He may stand his ground there and kill any person who attempts to enter by force. In such a case the owner or any member of the family, or even a lodger in the house, may meet the intruder at the threshold, and prevent him from entering by any means rendered necessary by the exigency, even to the taking of his life, and the homicide will be justifiable."
Id., 231 Md. at 361, 190 A.2d at 542, quoting Clark and Marshall, Law of Crimes, (6th ed. Wingersky rev.), § 7.03, pages 436-37.
This principle is known as the "Castle Doctrine", "the name being derived from the bedrock principle that 'a man's home is his castle' and his ultimate retreat." Barton v. State, 46 Md. App. 616, 618, 420 A.2d 1009, 1010-1011 (1980). A man "is not bound to flee and become a fugitive from his own home, for, if that were required, there would, theoretically, be no refuge for him anywhere in the world." Barton, 46 Md. App. at 618, 420 A.2d at 1010.
A person does not have to be the owner of the home or the head of the household in order to be able to invoke the "Castle Doctrine." Instead, "any member of the household, whether or not he or she has a proprietary or leasehold interest in the property, is within its ambit . . . ." Barton, 46 Md. App. at 619-20, 420 A.2d at 1011.