By accusing the king of murder, he signed his own death warrant. 因被指控谋杀国王，他签署了死刑执行令。 I saw this example sentence in Collins dictionary but I don’t understand it. Its translation in China means he signed the death warrant because he was accused of murdering the king. The logic is messy. My understanding to English version is he accused the king of murder then out of scare or justice he just signed the death warrant to put himself to death. And I still don’t know why it is “By” here unless he is the king.