What if the rebels refuse to ransom their captives and keep them imprisoned?

Primary text

It is possible that the army of justice is permitted to imprison the captives they hold from the rebels' side to facilitate the release of their own captives through this reciprocal detention. Alternatively, it is possible that imprisoning the rebels' captives is not permitted, and they must be released, because the transgression of imprisoning the captives of the army of justice is due to the actions of others (the rebels).