1 Kings 16:18

In the twenty-seventh year of Asa king of Judah, Zimri reigned seven days in Tirzah. Now the people were encamped against Gibbethon, which belonged to the Philistines.

The people who were encamped heard that Zimri had conspired, and had also killed the king. Therefore all Israel made Omri, the captain of the army, king over Israel that day in the camp.

Omri went up from Gibbethon, and all Israel with him, and they besieged Tirzah.

for his sins which he sinned in doing that which was evil in the LORD’s sight, in walking in the way of Jeroboam, and in his sin which he did to make Israel to sin.

Now the rest of the acts of Zimri, and his treason that he committed, aren’t they written in the book of the chronicles of the kings of Israel?

Then the people of Israel were divided into two parts: half of the people followed Tibni the son of Ginath, to make him king, and half followed Omri.