Kai Zhuang: Police in Utah fear Chinese exchange student was kidnapped

Police in Utah believe Kai Zhuang, 17, has been kidnapped and is being held for ransom

Police in the US are searching for a teenage Chinese exchange student they fear has been kidnapped.

Kai Zhuang, 17, was last seen on Wednesday at his home in the town of Riverdale in Utah.

Police said it is possible he is being held against his will and is in danger.

Officers were alerted to concerns about Kai's welfare on Thursday evening by the school he was attending in Riverdale, which had been contacted by his parents at home in China.

Riverdale Police Department Chief Casey Warren said the parents told school officials they had been sent a ransom demand and a picture of their son, indicating he was abducted.

Officers then visited the home of the host family where the missing teenager was living, who said they were unaware he was not in the house at the time.

The family told police they had seen Kai on the evening of 27 December and may have heard him in the early hours of the following morning.

Investigators initially said they believed the boy had been "forcefully taken from his home".

But on Friday, Mr Warren told reporters there was currently no evidence to suggest that.

He said officers are working with the FBI in the US and authorities in China and that "several investigative efforts are underway" to find him.

The force has issued an endangered missing person advisory for Kai. They were unable to use the US alert system for missing persons as no suspect had yet been identified, Mr Warren said.