The mysterious disappearance last month of a Saudi dissident living in Montreal after visiting the kingdom’s embassy in Ottawa has sent fear rippling across Canada’s community of Saudi exiles.

While the gravest concerns were allayed when Ahmed Abdullah al-Harbi, 24, reappeared recently in Saudi Arabia, his fellow activists suspect he was coerced to return to the kingdom and are afraid he is providing Saudi authorities with information that jeopardizes them and their families.

These fears are most acute among Saudi activists who have tried to keep a low profile and avoid attracting unwanted attention from the Saudi government.

“They’re normal people from Saudi Arabia who left Saudi Arabia and disappeared out of sight,” said one dissident in Canada, who spoke on the condition of anonymity, fearing retribution by Saudi authorities. “But now, they’re exposed. Ahmed revealed their names. And they’re worried they’re going to be targeted, that at any moment something will happen.”

In recent years, Saudi authorities have repeatedly tried to intimidate critics living abroad, pressured their relatives who remain in the kingdom, and in some instances abducted dissidents and repatriated them to Saudi Arabia.

On Friday, the U.S. intelligence community gave Congress a report concluding that Saudi Crown Prince Mohammed bin Salman had approved an operation that killed Saudi journalist Jamal Khashoggi inside the kingdom’s consulate in Istanbul in 2018. The report, prepared by the Office of the Director of National Intelligence, noted “the Crown Prince’s support for using violent measures to silence dissidents abroad.”

Harbi, who entered Canada in 2019 and was granted asylum, had worked on several projects with other Saudi dissidents in Canada, according to friends. This included involvement in an opposition talk show on YouTube and participation in a network of volunteers active on Twitter to counter Saudi Arabia’s “flies,” the government-backed operation that attacks social media users critical of authorities.

“We have people who had fake names. They now know who they are,” said Omar Abdulaziz, a prominent Saudi dissident and longtime Canadian resident who runs both the television show and the opposition Twitter network. Saudi authorities may also be in a position now to learn intimate details of these operations, he said.

Abdulaziz and two other of Harbi’s friends said in interviews that Harbi disappeared a few weeks ago, blocking them on Snapchat and leaving all of their common messaging groups.

Harbi then called at least two friends, Abdulaziz and Omar al-Zuhairi, and told them he had gone to the Saudi Embassy, where he was interrogated and pressured to reveal the names and details of people in the activist network, the two friends said. Harbi said on the calls that he had provided names of other activists.

In a recording of one call obtained by The Washington Post, Harbi, between long pauses, says that he was asked questions about Abdulaziz and his work. Harbi said he felt his family in Saudi Arabia was being subtly threatened. Describing his visit to the embassy, he said, “When you enter, you feel like you’re Khashoggi.”

Harbi told Abdulaziz that embassy staff gave him a plane ticket to Saudi Arabia and took him to the airport but that he told his escorts he had decided against returning to the kingdom and got away. Harbi then vanished for nearly three weeks.

On Feb. 16, Abdulaziz raised the alarm on his popular Twitter account.

Two days later, a new Twitter account for Harbi appeared. Absent were the previous references to Saudi dissidents, prisoners and Khashoggi. The new account was topped with a photo of the crown prince.

Harbi’s first tweet celebrated being back in his homeland. A photo showed an airplane ticket with his name dated Feb. 7.

Public Safety Canada referred questions about whether Canada would be probing how Harbi ended up in Saudi Arabia to the Royal Canadian Mounted Police, which declined to comment. Immigration, Refugees and Citizenship Canada said it could “neither confirm nor deny” whether he had sought asylum in Canada, citing “reasons of privacy.”

The Saudi Embassy in Canada did not respond to a request for comment about Harbi.

Abdulaziz is the best-known activist in Harbi’s circle. Abdulaziz moved to Canada almost two decades ago and became an asylum seeker, then a Canadian citizen. Over time, he became active against what he perceived as injustices carried out by the Saudi government. His YouTube show criticizing the government has become extremely popular.

In 2018, he said his phone was hacked, and Saudi agents traveled to Canada to try to lure him back to the kingdom, according to a recording of that conversation. He said his family in Saudi Arabia, now under a travel ban, has stopped talking to him, and two brothers and more than 100 of his friends are in prison for having contact with him.

Another Saudi who has sought safety in Canada, former top Saudi spy chief Saad Aljabri, has accused Mohammed of targeting him for assassination, filing a lawsuit last year against the crown prince. The lawsuit also alleges that two of Aljabri’s children were detained in Saudi Arabia to pressure him to return. The Saudi government has accused Aljabri of embezzling public funds.

The Saudi dissident who spoke on the condition of anonymity oversaw Harbi’s work with the Twitter network, known as the “bees.” The dissident said that he had felt increasingly vulnerable in recent months but that it became far worse after Harbi returned to Saudi Arabia.

“Ahmed used to eat from my plate, and I his. He was truly with us. He knew our secrets. He knew our lives. He knew everything about us,” the dissident said.

He said he worries that Saudi authorities could now pressure — or even torture — Harbi to obtain information about the circle of dissidents. If their names are revealed, authorities could threaten their families in Saudi Arabia. The Saudi government has often placed travel bans on the relatives of dissidents as a way to intimidate them.

Fearing they could be targeted for violence even in Canada, the exiles said they already avoid Saudi diplomatic missions so they don’t end up like Khashoggi.

“I’ve never come out with my name or my photo or my resemblance or anything. Always incognito. Not even on Twitter do I have my name or information about me or my city, nothing at all,” said the anonymous dissident.

“But if I simply take one step forward and come out with my real name or photo,” he said, his words slowing down, “then it’s like I gave them the green light to take my family, to arrest my brother or sister or father or mother.”

Amanda Coletta in Toronto contributed to this report.