A Chinese exchange student who fell victim to a “cyber-kidnapping” scam, in which his parents were extorted for $80,000, was found alive but “cold and scared” in a tent in the Utah wilderness, police said.

Kai Zhuang, 17, was reported missing on Thursday after his parents in China told officials at his host high school in Riverdale, Utah, that he appeared to have been kidnapped and a ransom had been demanded.

The case followed a typical pattern for cyber-kidnapping, in which “kidnappers” tell a victim to isolate and provide pictures as if being held captive – photos that are then sent to the victim’s family to extort a payment. The victims comply under the belief their family will otherwise be harmed.

After analysing bank records, purchases and phone data in a days-long search, police became convinced he was isolating in a tent about 25 miles (40km) north in a large area near Brigham City.

“Due to the cold weather in Utah this time of year, we became additionally concerned for the victim’s safety in that he may freeze to death overnight,” the Riverdale police department said after he was found on Sunday.

A sergeant hiking on foot up a mountainside discovered Kai’s tent – which had no heat source, only a heat blanket, a sleeping bag, limited food and water and several phones that were presumed to be used to carry out the cyber-kidnapping, the department said.

The detective “contacted the victim inside the tent and found he was alive but very cold and scared”.

After being rescued, Kai “requested a warm cheeseburger” and to speak to his family, who had paid $80,000 to bank accounts in China during the scam, according to Riverdale police.

Kai’s host family in Riverdale had initially been unaware he was missing, having heard him in the kitchen in the morning on the day of his disappearance.

Local police worked with the FBI, the US embassy in China and Chinese officials to find the missing teenager.

The Chinese embassy in Washington had advised its citizens living in the US to bolster safety awareness, take necessary precautions, and stay vigilant against virtual kidnapping and other forms of telecom and online fraud, a spokesperson said.

Cyber-kidnappers have been targeting foreign exchange students recently and, in particular, Chinese foreign exchange students, according to Riverdale police.