Sahand Nourmohammadzadeh, who was detained during recent nationwide protests, faces two new charges of "spreading lies" and "disturbing public opinion," according to his defense attorney Hamed Ahmadi.
The new charges emerged after the release of an audio file in which Nourmohammadzadeh detailed his experience of torture during detention.
Nourmohammadzadeh told the BBC's Persian Service earlier this month that his initial trial lasted only seven minutes and he had been subjected to torture and mock executions throughout his arrest and imprisonment.
Following the release of the audio file, Nourmohammadzadeh was transferred to a solitary confinement cell at the Rajai Shahr prison.
Ahmadi told the Emtedad website that since his client's transfer to solitary confinement, he has had no news about Nourmohammadzadeh and that Rajai Shahr prison officials have denied any contact between the prisoner and his family or attorney.
Nourmohammadzadeh was arrested on October 4 during nationwide protests in front of his home in the Iranian capital of Tehran.
On November 7, Tehran's Revolutionary Court sentenced him to death on charges of "waging war against God through destruction and setting fire to public property, inciting to commit crimes against national security, and disrupting public order and tranquility by participating in gatherings."
However, after the country's Supreme Court ordered Nourmohammadzadeh's case to be referred to a parallel branch of the Revolutionary Court, his lawyer announced the cancellation of his client's death sentence on March 30. The charge of "waging war against God" against the political prisoner still remains.
The death of 22-year-old Mahsa Amini on September 16 prompted tens of thousands of Iranians to take to the streets to demand more freedoms and women's rights in the biggest threat to the Islamic government since the 1979 revolution.
The Islamic republic's judiciary has executed four detained protesters in trials that lacked fair conditions, according to numerous rights groups. Furthermore, several reports have emerged detailing torture, violence, and sexual assaults against detainees taken into custody during the protests.
Human rights groups have decried the push for harsh sentences, noting that political prisoners in Iran are already deprived of many of their rights, including access to their chosen defense attorney.