Killing an apostate, the right thing to do

o5.1 An expiation is due to Allah Most High from anyone who kills someone unlawful to kill, whether the killing is through a mistake or is intentional, and no matter whether retaliation (def: o3) or an indemnity (o4) is obligatory or not.

o5.2 The expiation consists of freeing a slave (def: k32), or if one cannot, then two consecutive months of fasting. (O: There is no difference in this precedence order whether the killer is legally accountable or not, as when he is a child or insane, in which case the guardian must free a slave on his behalf. (A: Though if a child fasts, it fulfills the expiation.))

o5.4 (O: There is no expiation for killing someone who has left Islam, a highwayman (def: o15). or a convicted married adulterer, even when someone besides the caliph kills him.)