What happened to the Israelite who brought a Midianite woman into the camp in the sight of Moses?

Phineas the priest took a spear and thrust a spear into the bodies of both the man and the woman. [25:8]

What did God do to stop them from sleeping with the Moabite women and worshiping Baal of Peor, and how many died ?

God sent a plague so that those who died were 24,000 in number. [25:8-9]