Is a mother considered a killer if her infant son dies after she covered him and left him crying for ten hours?

If a mother causes the death of her infant by placing a cover over its face, two things are incumbent upon her: expiation by fasting for two consecutive months (if she cannot find a believing slave to free), and paying the blood money (diyyah) to the infant's heirs. The blood money is incumbent upon the mother's Aqilah (her agnatic relatives and paternal kin), unless the heirs pardon her.