Saturday marks the third anniversary of the imprisonment of seven leaders of Iran's Bahai religious community. BBC Persian's Kambiz Fattahi in Washington says their treatment reflects the situation faced by many minority groups in Iran.
In March, Ashraf Khanjani passed away in Tehran at age 81.
Hundreds of people attended her funeral, but her husband, Bahai leader Jamaloddin Khanjani, was not among them.
Instead, he was in prison, barred by Iranian authorities from attending the ceremony.
Mr Khanjani is one of seven imprisoned leaders of Iran's Bahai community, the country's largest non-Muslim religious minority, which Iran's Shia Muslim political and religious establishment views as a heretical sect.
He, Fariba Kamalabadi, Mahvash Sabet, Afif Naeimi, Saeid Rezaie, Vahid Tizfahm and Behrouz Tavakkoli were sentenced last year to 20 years in prison, after their conviction on charges including co-operation with Israel, propaganda activities against the Islamic order, and "corruption on Earth".
That conviction by a branch of the Revolutionary Court in Tehran sparked an international outcry. The UN, the US and the EU have called for their release.Human waste
Nobel Peace Prize laureate and human rights lawyer Shirin Ebadi says her former clients are innocent.
"If an impartial judge were to try them," Ms Ebadi said, "they would be freed immediately."
Critics of Tehran say the persecution of the adherents of the Bahai faith has a political character. Human rights activist Ali Afshari says as a theocracy, Iran considers the growth of other faiths a serious threat to its existence.
"If it leaves the space open, religious minorities will grow that would harm the stability and existence of the political system," says Mr Afshari, who lives in the US.
Meanwhile, the two women in the group - Ms Kamalabadi and Ms Sabet - were recently sent to Qarchak prison, 40km (25 miles) south of Tehran, a move that worries their family and friends.
Ms Kamalabadi's brother, Iraj, says the prison is overcrowded and filled with human waste due to inadequate plumbing.
He says its 300 to 400 prisoners are crammed into one large room with no fresh air.
Mr Khanjani's niece, Nika Khanjani, an American citizen living in Canada, says she cannot freely communicate with her cousins in Iran.
"It is almost as if we are always speaking with an audience on the phone line," she says. "I try to edit conversations so there is nothing that would be seen as incriminating.
"For years they were saying 'thank God everything is fine', even though I knew it wasn't fine. They knew I knew it wasn't fine. In the past year their voices express a lot of exhaustion, fatigue and sadness."
Iranian officials dismiss claims of systematic discrimination against Bahais and say no groups are persecuted on religious grounds.
But the experiences reported by evangelical Christians and non-Shia Muslims belie that assertion.
Earlier this year, Tehran Governor Morteza Tamaddon publicly denounced Iran's evangelical Christians as "deviant" and "corrupt".
An estimated 100 evangelical Christians are currently imprisoned in the country, Iranian Christian activists say. Among those is Yusef Naderkhani, convicted of apostasy and sentenced to death in the northern Gilan province.
Rights groups say members of Iran's Nematollahi Gonabadi Sufi Order have also come under heavy pressure, and many of their places of worship destroyed.
Sunni Muslims in Tehran have long complained authorities will not permit them to build a mosque.
In the past year, roughly 200 Sufis, or dervishes, have been charged with insulting Iran's Supreme Leader Ayatollah Ali Khamenei and acting against the country's national security, says Mostafa Azmayesh, the Sufi order's spokesman outside Iran.
Although Mr Khanjani and the other Bahai prisoners are being held on political and security charges, Ms Ebadi says Iranian Bahais have no involvement in politics.
Mr Azmayesh makes a similar point. "Dervishes in Iran are being oppressed because of their belief in the separation of religion and politics," he says.