"In the tenth book I will include commandments regarding pure and impure things. And I have called this book the Book of Purity."

56. The Impurity of a Corpse - Tumas Mes

If a person (or utensil) touches a grave or a corpse or a severed limb or moves it or comes directly above or below it or is under the same roof with it he becomes impure for seven days, as it says "One who touches the corpse of any human being shall be impure seven days... if a man dies in a tent anyone who comes into the tent and everything that is in the tent shall be impure seven days".¹ Utensils (other than earthenware) that touch a person who has been in contact with a corpse, and persons who touch such utensils, are impure for seven days, as it says "[Anyone who touched a corpse...] you shall wash your clothes on the seventh day and become pure"²; but a person who touches such a person is only impure for one day, as it says "[And anything that the impure person touches becomes impure] and the person who touches [him] becomes impure until evening".³ Utensils that have been in contact with a corpse are treated like the corpse itself as regards touching, as it says "[And anyone who touches on the field] one killed by the sword or a corpse [or a human bone or a grave shall be impure seven days]"⁴ -- the sword is like the one killed by it. Rabbinically, one who goes out of the land of Israel also becomes impure.^a

Sources:
1. Num. 19:11,14	a. 1:1 (and see 2-3),5-7,10; 2:15; 3:1; 5:1-4,6; 11:1
2. Num. 31:19,24
3. Num. 19:22
4. Num. 19:16