The woman who was slain, that is, the Midianite woman, was named Cozbi. She was the daughter of Zur, a leader of one of the ancestral houses of Midian.

because they've acted deceitfully, bringing trouble to you in this incident at Peor with Cozbi, daughter of a prince from Midian, who was killed during the plague that came about because of the incident at Peor."