Roman Catechism 28.16

Chapter 28 — Part III: The Decalogue — The Fifth Commandment

Section 16. Finally, if we consider the numerous means by which murder may be committed, the law admits of no exception. Not only does it forbid to take away the life of another by laying violent hands on him, by means of a sword, a stone, a stick, a halter, or by administering poison; but also strictly prohibits the accomplishment of the death of another by counsel, assistance, help or any other means whatever.