(CNN) -- Human rights attorney Mohammed Mostafaei helped bring the world's attention to his client, Sakineh Mohammedie Ashtiani, a 43-year-old mother of two who was set to be stoned to death for allegedly committing adultery in Iran.
And in the process of his very public campaign to clear his client's name, Mostafaei may have also turned the Iranian government's spotlight on himself.
On Saturday, while the world was rallying in support of Ashtiani, hoping to pressure the Iranian government to reverse her death sentence, human rights groups say Mostafaei was being questioned by Iranian authorities for four straight hours in Evin prison before being released.
His crime? According to Rudi Bakhtiar from the International Campaign for Human Rights in Iran, Mostafaei was being pressured for making the Ashtiani case too public.
"The reason why Mr. Mostafaei is under fire is no doubt because of the worldwide attention concerning the Ashtiani case," she said. "And this is something the Iranian government does not like at all."
Mostafaei told CNN in July that he had been arrested once before, shortly after the post election turmoil in 2009, and that he knew the risks he was taking by speaking so publicly about the Ashtiani case. But he also said that risk wouldn't deter him from speaking out about human rights abuses in Iran.
Now it seems his family may be paying the price. Bakhtiar and other human rights advocates said Mostafaei went into hiding on Saturday to avoid arrest.
But Bakhtiar said, the Iranian authorities still managed to get their message across.
"His wife and his brother in-law were picked up when they went to his office to get his car, " Bakhtiar said. "The authorities were outside Mostafaei's office waiting to arrest him. Instead they arrested his wife and his brother-in-law. Then they called his wife's father and told him, 'We will release them as soon as Mostafaei turns himself in.'"
Mina Ahadi, from the International Campaign Against Execution, says the Iranian government is holding Mostafaei's relatives "hostage," and that the International community needs to keep speaking up and speaking out as they have for Ashtiani.
"I think it is a very dangerous situation for Mr. Mostafaei," she said. "If he were to present himself to the authorities, he might receive 10 to 15 years in prison, and I think we must put pressure on the Islamic regime so that his wife and brother will be released."
Bakhtiar says that unfortunately cases like Mostafaei's are far too common in Iran.
"Other attorneys have been arrested similarly when they have tried to advocate for certain people. This is something the government of Iran has tried over and over again -- to hush, using fear and intimidation tactics and also imprisoning anyone that they feel is threatening," she said. "The Islamic Republic likes to keep their stoning cases and their executions very quiet."
But for now one case Mostafaei has advocated for so diligently remains very public.
Next week, human right's groups say, the Iran judiciary may release their final judgment in the Ashtiani case, deciding whether to reinstate her sentence of death by stoning, execute her by another means or possibly even grant her a reprieve.