The spell has the following to say:
a soul is present in any corporeal remains for which the creature has not been resurrected or previously animated as an undead. a soul can also be obtained from trap the soul, magic jar, or similar magic.
but the spell doesn't outright state that a soul is required, at least on the d20PFSRD. As written, I am unsure if a corpse that had already been used for Animate Undead is a valid target for a further casting of Animate Undead. Can I cast Animate Undead on the same corpse again?
I have already looked at this question, but it is referring to a different spell and situation.