Ibrahim's lawyer, Elshareef Mohammed, said she had been sent "to an unknown house to stay at for her protection and security," the Daily Mail reports. "Her family had been threatened before and we are worried that someone might try to harm her," he said.

Officials promised that she would be released "in a few days" in late May, more than three weeks ago, according to the BBC.

Ibrahim's case incited international outrage over Sudan's treatment of Ibrahim, a wife and mother of two children. After giving birth to her second child in a Sudanese prison in May, Ibrahim was given two years before the courts would enact the death sentence. But the international pressure to free Ibrahim has paid off, a human rights activist told the Daily Mail.

"The Sudanese government was embarrassed by all the attention so they freed her," said Safwan Abobaker of Hardwired, a religious campaign group. "The Sudanese government needs to grant Meriam asylum or find a way to let her come to America right away."

Laws against apostasy — the act of abandoning one's faith — are on the books in 21 countries, and punishments range from fines to death, according to the Pew Research Center. They are most common in the Middle East and North Africa, where more than half of the countries have them, and there are five on the books in the Asia-Pacific region and four in sub-Saharan Africa. Sudan's legal code dictates that a pregnant woman not be executed until she has had two years to raise her child, according to Human Rights Watch.

Blasphemy laws are increasingly important tools for authoritarian governments and extremists in the Muslim world to gain and maintain power, according to Paul Marshall, senior fellow at the Hudson Institute's Center for Religious Freedom. And apostates pardoned from government sanction are often not safe from the court of public opinion, he notes:

While there has been no systematic study of the matter, and many punishments are not publicized, it appears that actual state-ordered executions are rarer than killings by vigilantes, mobs, and family members, sometimes with state acquiescence. In the last two years in Afghanistan, Islamist militants have murdered at least five Christians who had converted from Islam.

Vigilantes have killed, beaten, and threatened converts in Pakistan, the Palestinian areas, Turkey, Nigeria, Indonesia, Somalia, and Kenya. In November, Iranian convert Ghorban Dordi Tourani was stabbed to death by a group of fanatical Muslims. In December, Nigerian pastor Zacheous Habu Bu Ngwenche was attacked for allegedly hiding a convert.

In January, in Turkey, Kamil Kiroglu was beaten unconscious and threatened with death if he refused to deny his Christian faith and return to Islam.

U.S. politicians and residents called for Ibrahim's release with official statements and a petition garnering 53,000 signatures. Secretary of State John Kerry criticized the Sudanese apostasy law:

I urge the Sudanese judiciary and government to respect Ms. Ishag's fundamental right to freedom of religion. I also urge Sudan to repeal its laws that are inconsistent with its 2005 Interim Constitution, the Universal Declaration of Human Rights, and the International Covenant on Civil and Political Rights.