“The second of the 282 laws in the Code of Hammurabi, dating from the eighteenth century BC, states, “If a man charge a man with sorcery, and cannot prove it, he who is charged with sorcery shall go to the river; into the river he shall throw himself, and if the river overcome him, his accuser shall take to himself his house. If the river show that man to be innocent, and he come forth unharmed, he who charged him with sorcery shall be put to death.” – https://www.laphamsquarterly.org/magic-shows/miscellany/hammurabis-sorcery-law
That’s the only reference to sorcery, witchcraft, or magic in the Code, and it follows the general principles of lex talionis established elsewhere. You do harm to a citizen, an equal harm shall befall you (assuming you are of the same social class). You accuse a citizen of a capital crime, and you cannot prove it, you get executed instead. In the real world proving supernatural activity is by definition, going to be a tricky endeavor. Hammurabi punts by delivering judgement in the providence of nature. And if nature judges you innocent, your accuser gets killed himself. I’d like to think by drowning, there’s some symmetry there. But maybe there’s an entire class of executions reserved for false (or at least unwise) accusers.
There are some mythological implications for the trial by ordeal, as well. The first is that the origin of the Tigris and Euphrates rivers (likely, “the river”) was with the Tiamat at Marduk’s hand. Her weeping eyes became the Tigris and Euphrates. So, you know, by the source of Chaos your sorcery (seed of Chaos) shall be known. Second, the Mesopotamian water god charged with the care of the Tigris and Euphrates rivers was ENBILULU. So if you’re looking for a cult of witch-hunters, he’s your patron,
Practically, I’m not going to make all sorcery (spellcraft) a violation of nature, or of Law. Using harmful spells against people (which is to say humans, and more specifically citizens of the Holy Empire) though, is straight witchcraft. If there’s witnesses, you drown. If it’s in dispute, they give ENBILULU (which I would abbreviate to Embil, but damned if that isn’t confusing for Enlil) a chance to demonstrate your guilt…but again, be very sure before you accuse someone, because otherwise you end up in cement overshoes taking a long walk off a short pier yourself.
Note that sorcery against a citizen is a crime, but not one that’s limited to being committed by citizens / members of the Holy Empire. Any human, demi-human, humanoid, or vaguely Chaos touched creature can be convicted and put to death for the offense. Which, I’m pretty sure, doesn’t extend the same penalty for false testimony on accusing said godless heathen critter.