Bukhari, Volume 5, Book 59, Number 459.
Muhammed did not forbid raping the captive women. Instead he made an asinine claim that when Allah intends to create someone, nothing can prevent it. He told his men that coitus interruptus is ill-advised because it would be an attempt to thwart the will of Allah. He did not say a word against the rape of the captives, and by discouraging coitus interruptus, he supported forced insemination.
I know I have heard of this prohibition based on the Muslims false origin of the Jews, maybe it was only a fatwa. The Palestinian Authority Imam has proclaimed their false origin story, but that doesn’t stop the terrorists in the field.