Meriam Yahya Ibrahim was released a month later, but now two Christian pastors have been jailed and they also face a possible death sentence.

The Rev. Michael Yat and the Rev. Peter Yein Reith, both from the South Sudan Presbyterian Evangelical Church, have been charged with undermining the constitutional system and spying, offenses punishable by death or life imprisonment.

The clerics are charged with waging a war against the state and assault on religious belief.

“We know they have been arrested, but we don’t know where they are being detained,” said the Rev. Kori Romla Koru, general secretary of the Sudan Council of Churches. “We are trying to find them.”

Yat was arrested last year after visiting the Sudan Presbyterian Evangelical Church’s Bahri congregation in Khartoum, according to Christian Solidarity Worldwide, a charity that works on behalf of persecuted Christians.

The congregation had resisted the takeover of the church by a Muslim businessman, who had demolished part of the worship centre.

In December, police beat and arrested 38 Christians for worshipping in the church.

With Yat’s arrest, South Sudan Presbyterian Evangelical Church sent Reith with a letter to the authorities to demand his release. He was arrested on Jan. 11.

Human rights groups have expressed deep concern over the charges, warning that the two clerics could face torture.

“It is unacceptable that after enduring extended detentions without charge, the men now face extreme and unwarranted charges,” said Mervyn Thomas, CSW’s chief executive, said earlier this month.

Since the separation of Sudan and South Sudan in 2011, Sudan has forced out all foreign missionaries, raided churches and arrested and interrogated Christians on grounds that they belonged to South Sudan.