Numbers 19:12

‘Or a person who touches any unclean thing, whether a carcass of an unclean beast or the carcass of unclean cattle or a carcass of unclean swarming things—though it is hidden from him, yet he is unclean—will be guilty.

‘All the days of his dedication as a Nazirite to Yahweh he shall not go near to a dead person.

But there were some men who were unclean because of a dead person, so that they could not celebrate Passover on that day; so they came near before Moses and Aaron on that day.

“And you, camp outside the camp seven days; whoever has killed any person and whoever has touched any slain, purify yourselves, you and your captives, on the third day and on the seventh day.