Atonement Must be Made for Accidental Killing
Question :
I killed a person and I was forced to kill her against my will. Now I am ill and I cannot fast, so what should I do, may Allah reward you with goodness?
Answer:
Since the killing was an accident, you must atone for it, and the atonement is to free a believing slave; and if you do not find one, then you must fast for two consecutive months. You may not feed (the poor) for it, since Allah did not mention feeding (the poor) in the Verse, so the atonement remains incumbent upon one who is unable until he is able.
Source:
Ibn Jibreen
Fatawa Islamiyah, Vol. 6 Page 180