Then all the Israelites from Dan to Beer-sheba, as well as from the area of Gilead, marched out, and the group assembled as one body in the LORD's presence at Mizpah.
References for Judges 20:1
The commanders of the people and of all the tribes of Israel took their place in the assembly of God's people, four hundred thousand foot soldiers armed with swords.
And the Benjaminites got word that the Israelites had marched up to Mizpah. The Israelites inquired, "Tell us how this evil act happened."
So the Levite, the husband of the murdered woman, answered, "My secondary wife and I came to Gibeah of Benjamin to spend the night,
and the leading citizens of Gibeah tried to attack me. They surrounded me in the house at night and were determined to kill me. They abused my secondary wife until she died.
I took her, chopped her up, and sent her pieces into every part of Israel's territory, because they had committed a disgraceful act in Israel.