Iran’s Revolutionary Guard Corps arrested a Christian mother and her son on February 20, seizing their Bibles and other religious literature, as part of what Fox News calls “a brutal crackdown on Catholicism.”

“The arrest of two newly Christian converts – Anousheh Rezabakhsh and Soheil Zargarzadeh (mother and son, respectively) – in Urmia, a northern city in Iran, is very sad and concerning, especially as they both are dealing with health issues. It’s been more than two weeks that Iranian authorities have not provided any news on them,” said Eliot Assoudeh of the University of Nevada.

Assoudeh said Christianity is the fastest-growing religion in Iran, even though converts must risk their lives to attend underground churches.

News of the arrest comes from the Iranian Christian News Agency, also known as Mohabat News. According to Mohabat, Anousheh Rezabakhsh and her son Soheil Zagarzadeh Sani, also known as “Veronika” and “Augustine,” were arrested at their home by plainclothes officers. Neither of them had a prior arrest record. Soheil is a university senior who has been studying psychology.

Julie Lenarz of the Human Security Center in London told Fox News that “leaving Islam or converting to another religion is punishable by death in the Islamic Republic of Iran.” She noted that years of imprisonment, harassment, and torture are also common for Christians arrested by Iran.

Middle East Concern reports that Veronika and Augustine are “converts to the Catholic Church and were baptized in Istanbul, Turkey in August 2016.” A Facebook page has been created to draw international attention to their plight and the persecution of other Christians in Iran.

Another group of Christians was arrested last summer during a picnic. Three of them were able to raise bail and were released. The other two went on a hunger strike in February while in prison to protest their unfair treatment and became seriously ill. Although they have been imprisoned for over six months, they still have not been convicted of any crime.