Deuteronomy 22:26

But unto the damsel thou shalt do nothing; there is in the damsel no sin worthy of death: for as when a man riseth against his neighbour, and slayeth him, even so is this matter:

Cross-reference

In 2 Samuel 14:6, the woman of Tekoa describes a murder in the field — exactly the scenario this law uses as a comparison for the innocent betrothed woman.