Numbers 31:19
You yourselves will have to keep outside the tent-circle for seven days, anyone of you who has put any person to death or come near a dead body; and on the third day and on the seventh day make yourselves and your prisoners clean.
Numbers 5:2
Give orders to the children of Israel to put outside the tent-circle every leper, and anyone who has any sort of flow from his body, and anyone who is unclean from the touch of the dead;
Numbers 19:11-22
Anyone touching a dead body will be unclean for seven days:
1 Chronicles 22:8
But the word of the Lord came to me saying, You have taken lives without number and made great wars; I will not let you be the builder of a house for my name, because of the lives you have taken on the earth before my eyes.