ثُمَّ بَدَا لَهُم مِّنۢ بَعْدِ مَا رَأَوُا۟ ٱلْـَٔايَـٰتِ لَيَسْجُنُنَّهُۥ حَتَّىٰ حِينٍ
Summa badaa lahum mim ba'di maa ra-awul Aayaati layasjununnahoo hatta heen
Then, even after they had seen the signs, it occurred to them to imprison him for a time.
Innocence is established before this verse and imprisonment follows anyway, and the Arabic will not name who decided: the verb says only that it appeared good to them. No term is set either, ḥattā ḥīn, until a time, so the sentence has no length a prisoner could count down. The signs they had seen are āyāt, the noun that also names the verses of revelation, seen here and set aside all the same.