For three days last fall, Mike Zhang didn't know if his daughter, Juanwen, was dead or alive.

At home in China's Xinjiang province, the businessman could not reach the 20-year-old student who was studying economics at the University of Toronto. Her phone was off and she wasn't responding to his emails

In an exclusive interview with CBC Toronto, Zhang recounted the horror and stress of being at the centre of a missing person investigation that involved multiple police and government organizations investigating what turned out to be a scam aimed at extorting money from the families of young, vulnerable international students from China.

She's traumatized, but more so, embarrassed. — Mike Zhang, father

Before he even learned his daughter was missing, Zhang received a strange phone call one November day.

"I heard a man with a southern [Mandarin] accent who said, 'Hello, Mr. Zhang.' It gave me a bad vibe, so I hung up," Zhang said in Mandarin.

He didn't think much of it until his wife called a few hours later to report their daughter's friends were looking for her. Their phone rang again.

"He said, 'We have your daughter. Have one million [yuan] ready. Do not call the police or you'll get a dead body,'" Zhang told CBC Toronto. "The only thought I had was she will never be able to come back. Someone has murdered her — that was my first reaction. I was so distraught."

Late last year, Juanwen and two Chinese international high school students in the Toronto area fell victim to the ransom scam, which captured attention countrywide. Between September and November, the Chinese consulate in Toronto said it received about 10 calls daily from panicked parents and students, as the fraudsters sometimes posed as consul officials.

Hid at McDonald's

It started, Zhang said, when his daughter got a call at her rental home near campus. It was a man's voice, purporting to be from the local Chinese consulate.

The man said her personal information had been stolen, used to open a bank account linked to illegal dealings and that Interpol was looking for her.

The caller told her to go into hiding and cut off communication with anyone she knew. Otherwise, the criminals who stole her information could track her down and hurt her family.

She was also instructed to buy a burner phone, a phone card and to withdraw some cash. Once she did, Zhang said his daughter spent the first night hiding out at a McDonald's in Toronto. The next day, the scammers told her to leave the city because it wasn't safe, so she dutifully bought a bus ticket to Montreal, where she checked into a hotel and hunkered down.

Toronto police said the two high school students received similar calls, and also went into hiding.

Ottawa wants to bring in 450,000 international students by 2022, but the latest figures show there are 414,000 in 2016. A third of foreign students studying in Canada are from China. (Rogelio V. Solis/Associated Press)

'Dad, I'm fine'

In subsequent calls from the scammers, Zhang insisted on getting some proof his daughter was alive. He was sent an audio recording that sounded like his daughter saying, "Dad, I'm fine," but thought she sounded too calm to have been kidnapped.

Zhang called Toronto police, the Chinese embassy and consulate. Officials urged him and Juanwen's friends to keep trying to reach her.

Three days after she disappeared, Juanwen checked her email and saw dozens of messages. She realized it was all a scam and, when she contacted her family, so did they.

Education consul Wenjin Han, left, and vice-consul general Hong Hong from the Chinese consulate in Toronto. The consulate wants Canadian officials to take more responsibility for international students. (Martin Trainor/CBC)

"We never anticipated this kind of scam," Zhang said, adding that his daughter didn't want to talk about the incident.

"She's traumatized, but more so, embarrassed. She couldn't believe this happened to her."

Toronto police say there is an open file on the case but no other victims have come forward. They have no new information so they are not actively investigating the case.

The scam was also reported elsewhere in Canada. The RCMP confirms multiple incidents, with the "large majority" in British Columbia, but would not say more because the investigation is ongoing. The Mounties have set up a task force, offering experts to help other police forces investigate similar cases.

International student population growing

While all three Toronto-area students were found safe, the local Chinese consulate wants more done to protect international students because the federal government is issuing more student visas.

In 2015, the federal government set a target to grow its international student base to 450,000 by 2022. The most recent figures show that in 2016, there were already more than 414,000. About half lived in Ontario. A third of foreign students studying in Canada are from China.

The latest data provided by the federal government shows the provinces with the highest number of elementary, high school and post-secondary international students for 2016.

The Chinese consulate in Toronto says it issued four warnings about the ransom scam on its website last year, including three before the November incident. It also says it's been working with local Chinese media and community organizations to spread the word about the scam.

It is urging officials involved in bringing students to Canada to take more responsibility for them.

"There should be more connection between the students and their guardians, guardians with the schools, schools and school boards, and school boards with our consulate," said education consul Wenjin Han. "All these things need to be strengthened."

Hong Hong, the vice-consul general, pointed out the students were "not just here for academic achievements; they're here to grow up."

"We should provide a better environment for these young lives," she said. "They're facing tremendous problems, pressure, challenges. It's a pity it seems we still have a long way to go."