在法律中，当两个罪犯用受害人的鲜血密封一份契约时，这种行为已经构成犯罪，即使那两个罪犯后来发生争执举枪射杀彼此。
In law, when two criminals seal a contract with the blood of their victims, that act remains a crime, even if the two criminals later have a falling out and spray bullets at one another.