Bangkok police are searching for a Chinese tourist who went missing in the Thai capital, whose father received a ransom demand of five million yuan (S$932,000) for her safe return.

Media outlet Thai Examiner reported that the father of 27-year-old Xin Lei Lu had received a message on Chinese messaging app WeChat on June 7 at about 6pm, demanding he pay the ransom in order to secure Lu's release to Shanghai.

Lu resides in Shanghai with her family and had arrived in Thailand on June 5 with a group of more than 10 friends.

Upon receiving the ransom demand, Lu's father found a Chinese interpreter who alerted officers at the Phra Khanong Police Station of the incident. A report was filed at 7.30pm.

According to Thai media outlet Thaiger, staff members at a hotel that Lu was staying at — The Quarter Onnut Hotel — confirmed with Phra Khanong Police's investigative unit that Lu had checked in and left the hotel at around 3.11pm on June 7.

CCTV footage reportedly showed her walking out alone.

Lu had initially stayed at the Evergreen Place Siam Hotel in Bangkok's Phaya Thai district on her first night, before moving to the second hotel.

Thai Examiner reported that several hours after the report was filed, the Chinese interpreter informed Thai police that Lu's father had discovered that a flight ticket to Singapore had been reserved in Lu's name.

According to flight-tracking website Flight Aware, the Scoot flight — TR617 — departed Bangkok at 8.58pm on June 7, and landed at 11.35pm in Singapore on the same day.

However, checks with Thailand's Immigration Bureau and the Tourism Authority found no records of Lu having left the country, reported Thaiger, citing media outlet KhaoSod.

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This article was first published in The Straits Times. Permission required for reproduction.