Mohamed Al-Baqer's wife has published a letter he wrote whilst in detention in Egypt's notorious Scorpion Prison.
"I am fine, praise be to God," he wrote. "I am in good health." He added: "Keep me in your mind always."
The lawyer and founder of the Adalah Centre for Rights and Freedoms was arrested at the end of September after attending an investigation into his client Alaa Abdul Fattah, the prominent Egyptian blogger.
Both were swept up as part of a renewed crackdown following rare protests against the Sisi regime after the Egyptian whistleblower Mohamed Ali revealed widespread corruption in the government's inner circle.
Both Alaa and Al-Baqer were accused of belonging to and financing a terror group, which are common accusations levelled against anyone who speaks out against the government.
Despite the fact that pretrial detention should only be used in emergencies, Egypt has renewed Al-Baqer's many times, as a punitive and retaliatory measure regularly used to inflict psychological torture on detainees.
In his letter Al-Baqer expressed concern about his elderly mother, who would be highly vulnerable if she caught coronavirus. "How is mum? Is she taking her medicines regularly? Make sure her consultations with her doctors are only done via telephone," he said.
"My mother, my dear sister, my wife, my love, my heart, and my companion… when this imprisonment ends, and we return to our normal life again," Al-Baqer wrote.
Egypt currently has 3,144 cases of coronavirus and 239 deaths but experts believe the figures are far higher.
The health system is under serious strain after years of underfunding and several hospitals are closing their doors across the country as the number of medics testing positive continues to rise.
Despite other countries releasing prisoners in anticipation that a coronavirus outbreak inside jail would be lethal, Egypt has not only refused to release a significant number, but has continued to crack down on anyone it deems to be opponents.
On Saturday authorities added 13 people to the terror list for a period of five years for allegedly collaborating with the Muslim Brotherhood, including former parliamentarian Ziad Al-Alimi and BDS' Egypt coordinator Rami Shaath, who is the son of Palestinian politician Nabil Shaath.
The decision was issued without their lawyers present. Hundreds have been added to Egypt's terror list over the past several years, including a number of prominent members of the opposition.