So-called “virtual kidnapping” scams are on the rise in the Australian state of New South Wales, police warned on Friday. The scammers dupe Chinese students into thinking they have to pay to avoid deportation, before extorting lucrative ransoms from the victims’ families.

Four such fake kidnappings have been reported to New South Wales Police in the last month alone, the police said a press release. In each case, Chinese international students were targeted.

The scam begins when a Chinese student receives a phone call from someone speaking Mandarin and claiming to be an official from a Chinese embassy, consulate, or police department. The scammer tells the victim that they have been implicated in a crime, and must pay a large sum of money to avoid deportation and prosecution. 

The conversation then moves to chat apps such as WhatsApp and WeChat, where the victims are told to hand over up to AU$280,000 (US$186,000). Those unable to pay the full amount are instructed to take photos faking their own kidnappings and send them to the scammers, who then contact the students’ families back in China and extort the ransom money from them.

The scammers will continue to make threats and ransom demands until the families are unable to pay any more money, at which point they often contact law enforcement in China, NSW Police explained.

In one of the four cases recorded over the last month, the family of a 23-year-old female student paid a fake ransom of AU$270,000 before the student was tracked down by NSW Police officers. One 22-year-old woman handed over AU$20,000 before she was contacted by police, while two other teenage victims were found before any money was paid.

Chinese embassy police liaison officer Zhang Zhengping told Australia’s ABC News that law enforcement in China is working to crack down on the crime networks behind these scams. Chinese officials assured families that no government agents or officials would ever call students looking for money.