Chabad.org — English translation + Rashi
Torah Temimah points to Zevachim 9b (unit 4; single primary locus per emergency Core plan).
E-Daf.com — Zevachim 9b
HebrewBooks / Shas PDF
English: Rav said: A chatas slaughtered for the sake of a dead person is valid; why? “And he shall atone for him” is written, and there is no atonement for the dead.
No kapparah for the deceased — slaughter “for a dead person” does not invalidate, because the dead have no kapparah to receive.
If the slaughterer intends the chatas to atone for a deceased person, the offering remains valid. The verse’s “ve-chipper alav” presupposes a living subject capable of receiving atonement; the dead are simply not in that category, so the intent does not produce a pesul.