And the people that were encamped heard say, Zimri hath conspired, and hath also slain the king: wherefore all Israel made Omri, the captain of the host, king over Israel that day in the camp.

and the people in the camp heard that Zimri had not only conspired but had also struck down the king. So there in the camp that very day, all Israel proclaimed Omri, the commander of the army, king over Israel.