en_tn_condensed/num/25/06.md

brought among his family members a Midianite woman

"brought a Midianite woman to the Israelite camp to sleep with her". Balaam told the young women from Moab to act friendly to the Israelite men and invite them to feasts in honor of their god Baal. The men went to the feasts and worshiped Baal. God was angry and killed 24,000 Israelite men. Foreign women are often the source of problems in Israel. They caused the men to worship their false gods.

in the sight of Moses and all the community of the people of Israel

Here "in the sight of" means they heard about it, or found out about it.