Brent Christensen

Everybody was kind of really, really frightened, especially the females.

And just thinking about how many times you see young females, college students walking around in the area by themselves.

And I think it was a huge eye opener.

It got more frightening when this British grad student named Emily Hogan tells police that earlier the same day that Ying Ying went missing, a man tried to get her into his car.

She said a white male in a black sedan pulled up next to her, identified himself as an undercover police officer, and asked her to get in his car to answer a few questions about things going on in the neighborhood.

Emily described seeing mirrored sunglasses and being shown a badge.

She declined, and then she immediately calls the police.

Do you remember, like, hearing anything?

Police will have a, police, you'll hear, like, a scanner or a radio.

Emily Hogan is so rattled that she posts about the encounter on Facebook.

This is hours before Yingying's kidnapping.

She warns people, don't get in a car, even if they say they are police or have a badge.

If Yingying had just seen that post, perhaps she might never have gotten picked up.

One of the people watching that was someone very, very close to Ying Ying, her serious boyfriend, Xiaoding Hou.

I saw the videos.

I don't know what happened after she got into the car.

Yingying's boyfriend and her family wanted to do something that the FBI could not do, just find out for themselves exactly what happened to her.

Yingying's missing became a huge story in China.

This particular one got so much attention because Yingying was from a very ordinary family.

So to uncover every detail about Yingying Zhang's background, I traveled thousands of miles away from the American college town to the south of China to the town of Nanping.