The punishment for torturers in the hereafter is severe.
The Messenger of Allah ﷺ said:
إِنَّ اللَّهَ يُعَذِّبُ الَّذِينَ يُعَذِّبُونَ النَّاسَ فِى الدُّنْيَا
“Allah tortures those who torture the people in this life.” (Sahih Muslim)
The Islamic ‘aqeeda is not only a spiritual belief which leaves matters of justice and punishment to the Day of Judgement. Rather the Islamic ‘aqeeda is both spiritual and political obliging the Muslim ummah to practically implement all the sharia rules on earth through a state. These rules include a comprehensive judicial and punishment system.
The general principle for contracts, transactions and courts’ verdicts before the establishment of the Khilafah is that they stand and would not be annulled. However, cases involving people who harmed Islam and Muslims are excluded from this general principle and the Khilafah will hunt them down and bring them to court to face justice in this life.
The evidence permitting this is from the sunnah. When the Messenger ﷺ conquered Makkah he declared the blood of some people to be shed with impunity as they used to harm Islam and Muslims in Jahiliyyah. He asked that their blood be shed even if they hung themselves to the curtains of the Ka’bah. This is despite the Messenger of Allah ﷺ saying: “Islam removes that which comes before it”, as narrated by Ahmad and Tabarani from Amr ibn Al-As. This means the one that harmed Islam and Muslims is excluded from this hadith.
Since the Messenger ﷺ forgave some of them later, such as forgiving Ikrimah ibn Abu Jahl, the Khaleefah is allowed to start a lawsuit against them or forgive them. This applies to those who used to torture Muslims for saying the truth or those who defamed Islam. The hadith: “Islam removes that which comes before it”, [Ahmad, Musnad, 4/199] does not apply to them, for they are excluded from it, and a case is started against them according to the opinion of the Khaleefah.