Hi, I have read a horror story 2-3 years and couldn't remember the
name of the book. So I guess you could help me?

Summary: A couple comes to meet police chief (or detector) in his
office. They say that their son has vanished. There is no signs to
tell them that their son was there. The missing happens when the
family takes an elevator (lift) to go up. There are 2 elevators in 2
sides. Before the elevator door is closed, the son suddenly escaped
and run to the other elevator (which goes up too). It is too late for
his parents to get him, thus they waited until 2 elevators finish
going up. Then they were shocked when the boy is not there anymore.
Because there is no camera installed inside elevator thus the detector
couldnt find out what really happened inside the elevator where the
boy was. After interviewing people (a group) who inside that elevator
with the boy, he realised that those people in that group were the
survivors from a plane crash and had to survive by eating corpses
meat. Hence he knew the answer for the missing of the boy but dont
know how to explain to the boy's parents.

I appreciate so much if you can find the book which that story is in.

Servus