TEHRAN — The wife of Kavous Seyed Emami, the Iranian-Canadian environmentalist who died in an Iranian jail after being accused of spying, was barred from leaving the country on Thursday, her sons said.

The widow, Maryam Mombeini, 55, was stopped by plainclothes agents as she and her two sons, Ramin and Mehran, were boarding a Lufthansa flight to Frankfurt before continuing to Vancouver, British Columbia. Mrs. Mombeini, who has Canadian citizenship, was told she could not leave the country and her passport was seized, Ramin Seyed Emami said.

“They have ripped our family apart once,” said his brother, Mehran, referring to their father’s death. “Now they are doing it again, by keeping our mom in Iran.”

Both sons, who are also Canadian citizens, were allowed to board the flight, as were the family’s three German shorthaired pointer dogs.