(CNN) -- An Iranian court may render the final verdict Thursday in the case of Sakineh Mohammedie Ashtiani, sentenced to death by stoning in Iran for allegedly committing adultery.

That case was placed under review after her attorney, Mohammad Mostafaei, helped launch a worldwide campaign to clear her. Now, as Ashtiani's two children wait to hear word of their mother's fate, Mostafaei's family must also await word of his.

That's because Mostafaei, a prominent human rights lawyer, was being held Wednesday at a detention center in Istanbul, Turkey, where he has requested asylum, said Metin Corabatir, a representative in Turkey for the U.N. High Commissioner for Refugees. He allegedly entered the country with improper documentation, the agency said.

Turkey does not require visas for citizens from neighboring Iran to enter the country. As a result, it is the first place hundreds of Iranians fled to after the Iranian government cracked down on opposition activists and critics over the past year.

Human rights groups are urging officials to grant his asylum request because they say he could be in grave danger if he is forced to return to Iran.

There is no word yet on whether any nation is willing to accept him.

Mostafaei went into hiding July 24, after facing a lengthy interrogation at Iran's notorious Evin prison, the same day rallies were being held worldwide to draw attention to the Ashtiani case.

His wife and brother-in-law were reportedly arrested that night at his office in Tehran as they tried to gather his belongings.

The Iranian government has since released Mostafaei's brother-in-law, but human rights groups said they are holding his wife as collateral until Mostafaei returns.

In a now widely circulated open letter reportedly penned by Mostafaei and posted on the internet, the lawyer accused Iranian authorities of holding his wife "hostage." He also explained why he made the painful choice of leaving his wife behind.

"Despite the arrest of the person I love most in my life, I decided not to ever set foot in a judicial office where the interrogators do not abide by any basic laws," he wrote.

"Hostage taking is never legal" Mostafaei said. "I decided not to appear unless the interrogator's office tries hard enough to come and arrest me in my silo that I have built for myself."

Mostafaei was asked by CNN in early July if he was worried about his safety after bringing so much attention to Ashtiani, who was convicted of adultery in 2006 and condemned to die by the brutal method of stoning.

Mostafaei told CNN that he knew the risks -- he had been detained briefly after Iran's post-election turmoil in June 2009 -- but that would not stop him fighting for human rights. But it was that very fight that forced him to flee the country he calls home.

As part of that open letter, Mostafaei cried out to the Iranian government -- and to God -- for the strange twist in his fate.

"For the past few years all my thoughts have been towards saving people who did not deserve to die." he wrote. "I was so occupied with saving these people that I hardly got to see my dear wife and daughter. ... And for someone who has always worked towards justice and the interests of the Islamic Republic, is this the way I am paid back for my God-loving and human-loving actions?"

"I leave you and your interrogator at the mercy of God, the creator," he continued. "I hope that you won't let my child cry for her mother, not eating food and wanting her mother back. She needs to hug her mother. If through this separation from her mother she gets hurt, it's a sin that you have committed."

The Iranian government has not commented on the detention of Mostafaei's wife.

Meanwhile, human rights activists are urging the international community not to forget Ashtiani, who may soon die. Nor the man who tried to set her free