A mainland Chinese student in Hong Kong has been arrested on suspicion of wasting police resources over her role in her elaborately staged kidnapping that sought to trick her parents into handing over HK$5 million (US$637,000) in ransom.

The ruse came to light last Friday after the victim’s mainland parents received a video that showed what appeared to be blood covering their daughter’s body and reported it to police.

The student, 18, came to Hong Kong last year to take an associate degree course on advertising at Chinese University, according to a police source. Her parents live in Dongguan in Guangdong province and her father is a businessman.

In August, she came across a scammer online posing as a Shanghai police officer who accused her of being involved in a criminal case and during the “investigation”, she was duped out of HK$200,000 last month, the source said.

Over time, the scammer endeared himself to the victim and gained her trust. The student also developed feelings for her “Shanghai police” friend, according to the insider.

Later last month, the scammer made another attempt to con her out of money, this time more than HK$100,000, but when she went to the bank to wire the money, the suspicious transaction was caught by a bank teller and police were notified.

Despite being warned by officers, the student continued to believe she had a romantic connection with the scammer, but her parents stepped in and asked her to return home.

On Friday night, police received a report from the student’s parents, saying their daughter had been kidnapped in Hong Kong and a HK$5 million ransom was being demanded. The parents received a video, which purported to show their daughter covered in blood after being tortured.

Officers from the Kowloon West police regional crime unit took over the case and pored over a large quantity of security camera footage, which showed the woman had checked into a hotel in Mong Kok earlier in the day and then went out. Officers traced her to Tsim Sha Tsui but did not find her.

At this point, her parents were negotiating with the scammer over the ransom amount and its delivery method, the source said.

The woman returned to the Mong Kok hotel on Saturday afternoon and was arrested by awaiting officers. The student did not suffer any injuries and was being detained for questioning on Sunday.

According to the police insider, the student told officers she was helping her “mainland police friend” on a “mission” because she looked like a person wanted by the mainland authorities. She admitted she had been asked to create the video and send the footage to the scammer.

He then allegedly asked her to hide out and not to contact anyone until the “mission” was finished, which she did.

“In the video, what appeared to be blood was shown all over her from the head to legs,” the source said, but added the “blood” looked fake and eventually turned out to be ketchup.

Officers at first suspected she might have been conspiring with the scammer to fake the abduction.

Superintendent Alan Chung urged the public to remain vigilant while meeting friends over the internet. He said genuine law enforcement would not ask people to make money transfers through phone calls for asset check or for the investigation of cases.

“The so-called mission is a common tactic used by scammers to ask you to do something or stop you from contacting others or seeking help,” he said.

Hong Kong has seen a surge in deception cases in recent years. In 2020, there were 15,553 such cases, compared with 8,216 in 2019. In 2021, the number rose to 19,249.

In the first half of 2022, almost 40 per cent, or 12,326, of the 31,434 crimes reported to police were deception cases.

In the first six months of this year, police handled 10,613 reports of cybercrimes with financial losses totalling HK$1.58 billion. In the whole of last year, fraudsters conned victims out of HK$3.02 billion in 16,159 cases of technology crime.