Jubilees 4:31
30 He lacked 70 years from 1000 years because 1000 years are one day in the testimony of heaven. For this reason it was written regarding the tree of knowledge: “On the day that you eat from it you will die.” Therefore he did not complete the years of this day because he died during it. 31 At the conclusion of this jubilee Cain was killed one year after him. His house fell on him, and he died inside his house. He was killed by its stones for with a stone he had killed Abel and, by a just punishment, he was killed with a stone. 32 For this reason it has been ordained on the heavenly tablets: “By the instrument with which a man kills his fellow he is to be killed. As he wounded him so are they to do to him.”
Leviticus 24:20
18 One who beats an animal to death must make restitution for it, life for life. 19 If a man inflicts an injury on his fellow citizen, just as he has done it must be done to him— 20 fracture for fracture, eye for eye, tooth for tooth—just as he inflicts an injury on another person that same injury must be inflicted on him. 21 One who beats an animal to death must make restitution for it, but one who beats a person to death must be put to death.
Notes and References
"... The book of Genesis does not report how Cain died; the original author of Jubilees similarly skipped the subject. As far as he was concerned, Cain’s story ended with his being cursed and exiled ... The Interpolator saw here another fine opportunity to connect something from Genesis with a law that appears later on in the Torah (and thus to assert that the law had always existed on the Heavenly Tablets). Leviticus 24:19-20 ... the means by which the harm was inflicted. Cain’s invented death through the collapse of his house upholds both halves of the verse: Cain was killed as punishment for Abel’s murder, and he was killed specifically by his house’s stones because with a stone he had killed Abel ..."
Kugel, James L. A Walk through Jubilees: Studies in the Book of Jubilees and the World of Its Creation (p. 51) Brill, 2012