(CNN) -- Iranian authorities have arrested the wife and a brother-in-law of a lawyer who is defending a woman facing imprisonment and possible execution by stoning, a human rights activist said Monday.
Mina Ahadi, chairwoman of the International Committee Against Stoning, said the wife and brother-in-law are being held in Evin Prison and police have closed the Tehran office of lawyer Mohammad Mostafaei. The location of the lawyer himself remains unknown, Ahadi said.
Sakineh Mohammadie Ashtiani was convicted of adultery in 2006 and was originally sentenced to death by stoning, but the sentence was put on hold earlier this month after an international outcry.
Protestors rallied worldwide Saturday in support of her, pushing for her release.
Earlier this month, Mostafaei told CNN that his client confessed to the crime after being subjected to 99 lashes. She later recanted the confession and has denied wrongdoing, he said.
Iranian state media reported this month that the nation's judiciary chief halted the execution of Ashtiani.
"Although the verdict still stands and is definite, the execution has been halted on humanitarian grounds from the order of the honorable judiciary chief, and will not be implemented at this time," Malek Ajdar Sharifi, a judiciary official in East Azerbaijan province, told Iran's Islamic Republic News Agency.
CNN's Stefan Simons contributed to this report.