A man who taught mysticism in Iran faces the death penalty after already serving almost four years in prison, in a case that has sparked outrage among hundreds of supporters.

Mohammad Ali Taheri, founder of a popular spiritual group called "Erfan-e Halgheh," or "mysticism circle," has been kept in solitary confinement in Tehran’s notorious Evin prison since May, 2011. Taheri, who taught popular spirituality and meditation classes, was originally given a 5-year sentence for “insulting Islamic sanctities,” an offense that does not carry the death penalty as it does not involve the deliberate insulting of the Prophet Mohammad.

“The Iranian government has created an environment where people are in duress, and once a person is in duress it is easier to hate than love." 

- Anita Ghanaei, student of Taheri

But with just a year left in his sentence, authorities have changed the charges to “corruption on Earth,” which can potentially lead to a death sentence, according to his family. Yesterday, Taheri’s wife, daughter and brother attended a court hearing, when they were told to come back after the Iranian New Year, celebrated March 21, family members told FoxNews.com.

Hundreds of supporters gathered in protest outside the courthouse, prompting authorities to use tear gas and arrest more than 70, according to Taghato News.  

Taheri has endured a dozen hunger strikes while in solitary confinement and attempted suicide four times, according to supporters.

His internal organs are now failing, according to his wife.

If he is executed, he will be just one of more than 1,200 prisoners executed since President Hassan Rouhani took office in August of 2013.

Iran has about 220,000 prisoners, in a country with a total population of about 75 million, according to Gholamhossein Esmaili, Iran’s chief prison official.

Taheri’s teachings include belief that every human being deserves love, respect and equality before God and treating others as you would want to be treated. He also practiced a form of healing and relaxation through meditation.

“The government wants to call him a cult leader because his teachings go against what they want us to hear,” said Anita Ghanaei, a student of Taheri’s course. “The Iranian government has created an environment where people are in duress, and once a person is in duress it is easier to hate than love." 

Taheri has been denied access to his lawyer, according to his family.

The case may go beyond that of Iranian authorities cracking down on a spiritual leader, according to Ghanaei, who says Taheri was arrested when a man, whose wife left him, blamed Taheri’s teachings.

In July 2014, Taheri sent a letter to Ahmed Shaheed, the United Nations Rapporteur on the situation of human rights in Iran, detailing the abuses and torture he has endured.

Lisa Daftari is a Fox News contributor specializing in Middle Eastern affairs.