In a murky trial, the two men were later convicted of collaborating with a hostile power — the United States — but the precise nature of the accusations has never been made clear.
The senior Mr. Namazi, who had suffered from serious arterial blockages, was released last October for urgent medical treatment. At the time, his son was granted a week’s leave from Evin Prison for a brief reunion with his father.
While in Evin, Mr. Namazi “has endured prolonged solitary confinement, denial of access to medical care, and physical and psychological torture,” according to a statement from his lawyer.
Mr. Namazi’s relatives also spoke out.
“My family is of course gravely concerned for Siamak’s health and distraught that he has resorted to such desperate measures,” his brother, Babak, said in a statement provided by Mr. Genser. He said they “understand his frustration with the seemingly unending horror he has faced.”
“I am begging President Biden to hear my brother’s pleas,” he said.
News of the hunger strike came as nationwide protests have engulfed Iran for months, set off by the death of a 22-year-old woman in the custody of morality police, who had accused her of violating the country’s law mandating head scarves for adult women.
In his letter, Mr. Namazi pointed to a moment when “the whole world is witnessing how atrociously this regime can respond to those who dare demand their basic rights,” and urged Mr. Biden in his letter to harness his “moral compass and find the resolve to bring the U.S. hostages in Iran home.”
At least two American citizens, both dual nationals, are still being held by the Iranian government on charges of spying and threatening national security.
One, a 67-year-old businessman and conservationist named Morad Tahbaz, has been detained since 2018. The other, Emad Sharghi, also a businessman, was arrested in January.