Ss Perpetua and Felicity, martyrs: "murdered!"

So, too, many others; some they beat, others they killed.

-- Mk 12:1-12

The fifth commandment forbids direct and intentional killing as gravely sinful. The murderer and those who cooperate voluntarily in murder commit a sin that cries out to heaven for vengeance.

Infanticide, fratricide, parricide, and the murder of a spouse are especially grave crimes by reason of the natural bonds which they break. Concern for eugenics or public health cannot justify any murder, even if commanded by public authority.

-- CCC 2268