My father is loved by the Saudi people because his authority and legitimacy as an independent Muslim scholar set him apart from the state-appointed scholars. Using Islamic principles to support his arguments, he championed civil liberties, participatory politics, the separation of powers and judicial independence.

For almost two decades, he has vocally led the campaign against terrorism in Saudi Arabia. He has called for renewing religious discourse and argued for moderate Islam. I wonder whether he was arrested because of his popular, progressive stances, because since the ascent of Prince Mohammed bin Salman, nobody else is allowed to be seen as a “reformer.”

While reformers like my father sit in prisons, Saudi Arabia has embraced hard-liners like Saleh al-Fouzan, an influential state-sponsored cleric and a member of the Council of Senior Scholars. In 2013, Mr. al-Fouzan denounced a future where women would drive and claimed that the Shia and other Muslims who do not follow Wahhabi beliefs are infidels and that anyone who disagrees with that interpretation is an infidel. He has also pronounced all-you-can-eat buffet restaurants forbidden because they strike him as akin to gambling, which is banned in Islam.

In August, Mr. al-Fouzan was seated between King Salman bin Abdulaziz and Prince Mohammed at the royal court to signal his authority and importance. A few months earlier, during a meeting, the crown prince told Mr. al-Fouzan, “You are like my father.” In September, Mr. al-Fouzan issued a fatwa urging the state to kill political dissidents who promote sedition against the ruler. A month later, my friend Jamal Khashoggi was murdered.

In such a culture of fear, there is little hope for justice. The judiciary is being pushed far from any semblance of the rule of law and due process.

Even some judges from the specialized criminal court, which is trying my father, have themselves been detained after they declined to impose harsh penalties recommended by the attorney general in certain cases. A judge told me that judges recently appointed to the specialized criminal court live with fear.

Yet there are some judges in Saudi Arabia who have not submitted to the total control the monarchy seeks. In 2013, around 200 judges signed a public petition calling for real legal and judicial reforms, and condemned the “overwhelming crackdown and suppression of the real and patriotic voices.” They wanted the independence of the judiciary.