Niu Shulei, a Beiji border police officer, said there is no household registration information on Cui in the national system, he has no criminal record and is not listed as a missing person.

In the winter of 2014, Cui struck up a conversation with Niu. "In fact, he couldn't remember where he was from and could not provided us with an exact address," Niu said.

"But he repeatedly asked us to help find his relatives."

Using the vague information Cui gave the officers, they began making phone calls to each village within the area they suspected he came from. Eventually, they were able to obtain the phone number of Cui's elder sister.

"It was 2015 and the Spring Festival holiday was approaching," Niu said.

"We knew how urgent his desire was to be reunited with his family, so we went to Hongqiling."

In heavy snowfall, they drove for more than five hours. Niu gave Cui his mobile phone and told him to call his sister, but there was no signal, so they had to travel an extra 4 kilometers to the top of a mountain to make the call.

On the mountaintop, Cui made the call and finally heard his sister's voice, falling to his knees in the snow.

"After getting in touch with my sister, I planned to save some money before returning home," Cui said.

"As time has gone by, I have become more homesick. I want to return home as soon as possible."

Niu said Beiji border police are trying to find a way to send him back next month. "Traveling by train without an identity card is a big problem," he said.

"We hope to help him obtain his household registration at the local police department with all the information we can provide about him."