All evening May 21, the day Mahtab Mortezaei Farid graduated from George Mason University, she waited for her phone to ring.

Her father, in Tehran and too far away to attend, had promised to call after her ceremony. For a man who had devoted much of his life to educating young people, the education of his daughter carried special meaning.

A few days earlier, when they had last spoken, “he was excited, and he made me promise to send pictures,” she said.

But the call never came, and Mortezaei Farid, 26, figured her father had forgotten. The next morning, she learned from Bahai friends in Iran what had happened: At the moment her father was supposed to be calling, he was being arrested.

The Iranian government had not charged Kamran Mortezaei Farid, 58. Nor had it charged 15 of his colleagues who members of the Bahai community say were arrested simultaneously, though nine have since been released. But to his friends and family, the reasons for the arrests are clear:

They are Bahai, members of a religion not recognized by the Iranian government, and they had been providing higher education to Bahai students despite being banned from attending or teaching in universities in Iran. Leaders of the Bahai community have languished in prison for years.

And so the graduation party, planned for this past Saturday night at Mahtab Mortezaei Farid’s house in Vienna, became a vigil. Family members and friends read prayers from the founder of the 150-year-old religion, which began in Iran and considers that country its spiritual home.

The faith has 5 million to 6 million followers worldwide — 300,000 in Iran and 170,000 in the United States, with 3,000 in the Washington area.

In a husky, resonant voice, Mortezaei Farid sang a Bahai prayer. Afterward, she cradled a photograph of her father.

“The only thing he ever bought for me, for birthdays and everything, was books,” she said. “It’s so important to him. It’s just the major thing. I feel like doing this is his mission in life.”

That mission stretches back more than a quarter-century, to shortly after the revolution that ousted Iran’s monarchy and ushered in Islamic rule.

Under the new regime, Bahai university professors were fired and Bahai university students were expelled. Many Bahais were executed.

Bahais place a high value on education, and soon an underground movement began. Bahais with expertise in various fields volunteered to teach high school graduates.

Classes were held by correspondence or in private homes, and some students traveled 14 hours by bus to attend.

By the late 1980s, the movement became known as the Bahai Institute for Higher Education (BIHE). Many classes are now taught online.

The institute does not issue degrees certified by the Iranian regime, but over the years thousands of Bahai students have been educated there, and many universities outside Iran have accepted them into graduate programs.

Kamran Mortezaei Farid, an electrical engineer, helped found the program and taught classes. He is now its director.

“From the very beginning, he was there, and he would say: ‘This is my responsibility. I don’t want to leave something unfinished. This is my thing in the world that I want to do,’ ” said his sister, Jaleh Mortezaei Sadeghzadeh, who lives in Alexandria and attended the vigil.

Mahtab Mortezaei Farid recalled discrimination against Bahais from a young age. Many top elementary schools and high schools did not accept them.

One friend was required to sit apart from other students in second grade and was made to wear gloves to avoid “contaminating” other students.

Students also knew they could not take their BIHE education for granted.

“We always were in stress,” said Tiana Maleki, 29, a Bahai who attended BIHE after being barred from attending college in Iran.

She was at the vigil Saturday. “Every day, we had doubts if the next day we would come to class, if nothing would happen to us.”

After graduation, it was hard to find jobs in Iran, she said, because BIHE courses were not recognized by many employers.

“It’s just to gain knowledge, and then go to school outside Iran,” Maleki said.

When Mahtab Mortezaei Farid was 18, her mother brought her to the United States so she could attend college without fear; she graduated with a double major in psychology and neuroscience.

Although saddened, those at the vigil said the arrests did not surprise them.

Iran’s semiofficial newspaper, Kayhan, said they had been arrested on allegations that they had “secretly established a virtual university.”

“I expected it,” said Jila Tahmasebi, Mortezaei Farid’s mother. “We know that Bahais don’t have any rights in Iran, so all of us expect that. Even if we don’t do anything wrong, they can arrest us.”

Classes at BIHE are continuing, despite the arrests. But Mortezaei Farid has long felt ambivalent about her father continuing his work there.

“I’m not selfless like he is,” she said. “I have been wanting him to come here and be with me. Not that I don’t honor what he’s doing, but lately I’ve been telling him that maybe it’s time to pass it on to someone else, that maybe it’s time to come spend time with his family.”

At the same time, she said, during the graduation ceremony she felt a flash of understanding for his choices.

“When I was standing up there, I was thinking about it — that I had the chance to come here, and so many people who are much smarter than me for sure and who wanted this even more than I did are stuck there,” she said. “I kind of had the sense of being proud of him for helping that happen somewhat for other people.”

A few days ago, Mortezaei Farid received a voice mail. It was from her father, calling from Iran’s notorious Evin Prison, the only call he has been able to make.

“It was kind of heartwarming, because his voice wasn’t shaky. He sounded pretty strong,” she said. “He said, ‘I love you,’ and he sent kisses.”

He had kept his promise after all.