I almost posted something about Abel's murder and Cain's lie about it. Able's death was a homicide, but there was no king or legislature to make the law. So maybe it was not a murder.
In a world without law, revenge becomes the law. Genesis has other examples. I have no personal experience with revenge, but I do have an odd connection with it.
I'm adopted. Genetically, I am Asian, probably Filipino. Maybe Heinz 52, My Dad thinks that my birth parents were Ifugao headhunters, which is a tribe that sometimes adorns the cover of National Geographic. Rather by accident I found a book about them in a used book store. The book is pre-World War Two, so maybe things are different now, but they had a cowabunga, holy moly Red Rider violent society. They were so violent that even the Spanish had not been able to deal with them.
Genesis 4 mentions how Lamech killed someone for revenge. Later in Genesis the sons of Jacob killed all the men in a town for revenge.
On a slightly different subject, I remember being with my great grandmother at a Protestant Bible study. Somebody said that the word, sin, is sometimes translated demon.