Yes, but in the story God warned Cain not to give into sin, but Cain did anyway and killed his brother out of jealousy. So God cursed Cain. We would have tried

Yes, but in the story God warned Cain not to give into sin, but Cain did anyway and killed his brother out of jealousy. So God cursed Cain. We would have tried him for premeditated murder. There's nothing gray about killing someone out of jealousy. Sure, it's a human emotion, and we can all feel jealous at times. Doesn't make the act of murder a moral gray area.