en_tn/1ki/16/27.md

are they not written in the book of the events of the kings of Israel?

This question is used to either inform or remind the readers that the information about Omri is in this other book. This rhetorical question can be translated as a statement. See how you translated this in 1 Kings 15:31. AT: "they are written in the book of the events of the kings of Israel." (See: rc://en/ta/man/translate/figs-rquestion)

are they not written ... Israel?

This can be stated in active form. AT: "someone has written about them in the book of the events of the kings of Israel." (See: rc://en/ta/man/translate/figs-activepassive)