ثم بدا لهم من بعد ما رأوا الآيات ليسجننه حتى حين (12:35) بالانجليزي

(12:35) Then it occurred to them that they should cast him into prison for a time, even though they themselves had seen manifest signs *30 (of his innocence and of the guilt of their women).

Tafseer Abu-al-A'la Maududi

Page 239 English Traditional

*30) It occurred to them to imprison Prophet Joseph in order "to save face" after they had seen clear proofs of his innocence and of the guilt of their own women, for no other alternative was left, in their opinion, to undo the scandal that was spreading fast in the land. But it did not occur to them that in fact his imprisonment was his moral victory and the moral defeat of the rulers and the dignitaries of Egypt. By that time, Prophet Joseph had not remained an unknown person, for all and sundry had heard stories of his beauty and piety, and of the love the "ladies" had shown towards him. Therefore when those "wise" courtiers put into practice their plausible device to imprison him in order to reverse the doings of their "ladies", the common people must have drawn their own conclusions for they knew Prophet Joseph to be a man of pure, strong and high character. So it was obvious to them that he had committed no "crime" to merit imprisonment, and that he had been imprisoned because it was an easier way of escape for the chiefs of Egypt than to keep their own ladies under control.
Incidentally, this shows that imprisonment of innocent people without trial and due procedure of law is as old as "civilization" itself. The dishonest rulers of to-day are not much different from the wicked rulers who governed Egypt some four thousand years ago. The only difference between the two is that they did not imprison people in the name and for the cause of "democracy" but they committed unlawful acts without any pretext of law. On the contrary, their modern descendants make use of the specious pretences of honesty when they are acting unjustly. They first enact the necessary unlawful laws to justify their unlawful practices and then "lawfully" imprison their victims. That is to say, the Egyptian rulers were honest in their dishonesty and did not hide the fact that they were imprisoning people to safeguard their own interests, and not those of the community. But these modern disciples of Satan cast innocent people into prison to ward off the "danger" they feel from them, but proclaim to the world that their victims are a menace to the country and the community. In short, they were mere tyrants but these are shameless liars as well.