How does a captive pray in prison: by shortening and combining prayers, by shortening prayers only, or by performing each prayer separately?

If the captive is a resident, he must pray in full. However, if he is a traveler or was taken captive by the enemies, he is permitted to shorten his prayers, even if his captivity is prolonged.

Regarding combining prayers, if the captive is a resident, he should not combine prayers except in cases of extreme necessity, such as being deprived of water. In such a situation, he may combine prayers, provided it does not become a habit for him, and he must strive to perform prayers at their appointed times as much as possible. However, if he is a traveler, he is permitted to combine and shorten his prayers.