Getting away with murder

“Justifiable homicide is that which is committed either, 1st, by unavoidable necessity, without any will, intention or desire, or any inadvertence or negligence in the party killing, and therefore without blame; such as, by an officer, executing a criminal, pursuant to the death-warrant, and in strict conformity to the law, in every particular; or, 2dly, for the advancement of public justice; as, where an officer, in the due execution of his office, kills a person who assaults and resists him; or, where a private person or officer attempts to arrest a man charged with felony and is resisted, and in the endeavor to take him, kills him; or, if a felon flee from justice, and in the pursuit he be killed, where be cannot otherwise be taken; or, if there be a riot, or a rebellious assembly, and the officers or their assistants, in dispersing the mob, kill some of them, where the riot cannot otherwise be suppressed; or, if prisoners, in gaol or going to gaol, assault or resist the officers, while in the necessary discharge of their duty, and the officers or their aids, in repelling force by force, kill the party resisting; or, 3dly, for the prevention of any atrocious crime, attempted to be committed by force; such as, murder, robbery, house-breaking in the night time, rape, mayhem, or any other act of felony against the person. But in such cases, the attempt must be not merely suspected, but apparent, the danger must be imminent, and the opposing force or resistance necessary to avert the danger or defeat the attempt.” – Simon Greenleaf, A Treatise on the Law of Evidence (footnotes omitted; emphases in original)