30 And he lacked seventy years of one thousand years; for one thousand years are as one day in the testimony of the heavens and therefore was it written concerning the tree of knowledge: 'On the day that ye eat thereof ye shall die.' For this reason he did not complete the years of this day; for he died during it. 31 At the close of this jubilee Cain was killed after him in the same year; for his house fell upon him and he died in the midst of his house, and he was killed by its stones; for with a stone he had killed Abel, and by a stone was he killed in righteous judgment. 32 For this reason it was ordained on the heavenly tablets: With the instrument with which a man kills his neighbour with the same shall he be killed; after the manner that he wounded him, in like manner shall they deal with him.'
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