The two sons of a Canadian-Iranian professor who died in a Tehran prison last month say their mother, Maryam Mombeini, was temporarily detained by Iranian authorities while trying to board a flight to Canada early on Thursday.

The sons were allowed to leave and are en route to Vancouver. All three members of the family are dual citizens of Iran and Canada, and previously lived in Toronto and Vancouver.

Mombeini, 55, was later released, but her Iranian passport has been confiscated, according to her son, Ramin Seyed-Emami.

"She basically begged us to get on the plane, and to just get the hell out of there," he said.

He said she still has her Canadian passport and has returned to her home in Tehran. Her plans were not immediately clear.

"My mother has already gone through so much in the past couple of weeks since my father's death. The emotional distress we've been going through is just insane," he said.

'We couldn't take it anymore'

Seyed-Emami said his family had been a victim of harassment and intimidation by the Iranian authorities, including a "smear campaign" that aired on national television.

"We just wanted to get out of the country as soon as we could.... We couldn't take it anymore," he said.

"They've messed with the wrong family. There's no way I'll stay silent about this until she's safe."

Authorities in Tehran say his father, Kavous Seyed-Emami, who was 63, committed suicide while in Iran's notorious Evin prison — just two weeks after being arrested on suspicion of espionage and spying.

Family and friends do not believe he took his own life. The family's request for an autopsy was denied by Iranian authorities.

Omid Memarian, deputy director at the New York-headquartered Centre for Human Rights in Iran, said he was in touch with the family when Mombeini and her sons were separated.

He said they made it through to the last security gate before Mombeini was told she was forbidden to leave Iran, and arresting authorities would not comment on why she couldn't leave.

"It was a shock for everyone," he said. "I think it's horrifying for a family that's never been in politics."

Memarian, who in 2004 was detained in the same prison where Seyed-Emami died, said he believes the move is part of a systematic detention of academics, journalists and activists in Iran.

"It's absolutely to [silence] the rest of the family, but this is not something I think they are going to do," he said.

Canada responds

The parliamentary secretary to Foreign Affairs Minister Chrystia Freeland, Omar Alghabra, will be greeting the brothers on their arrival in Vancouver, Seyed-Emami said.

In a tweet, Freeland said she was "outraged" Mombeini had been detained, and demanded that she be allowed to return to Canada.

I am outraged to learn that Maryam Mombeini, widow of Kavous Seyed-Emami, was barred from leaving Iran. We demand that, as a Canadian, she be given the freedom to return home. —@cafreeland

Kavous Seyed-Emami, who, like his family, was a Canadian-Iranian dual citizen, was a U.S.-trained scholar in sociology and the managing director of the Persian Wildlife Heritage Foundation, which seeks to protect Iran's rare animals. He had recently completed a six-month sabbatical at the University of Lethbridge.

Canada has no embassy in Iran. The two countries broke off diplomatic relations in 2012, and Italy now handles Canada's interests in the country.​

Ontario MP Ali Ehsassi who is also Canadian-Iranian, said he has been in communication with the family, and also plans to meet the sons at the airport in Vancouver on Thursday.

The incident is "very disappointing given the reality that the family has been through an incredibly difficult time," he said.

"Having to deal with this latest development, it's certainly something that breaks one's heart," he said.

​With files from Laura Lynch and Briar Stewart