It Seems JZK is Missing.

I will now list possible reasons.

1. He is injured somewhere and cannot walk and is not in the open.
2. He is kidnapped.
3. Suicide.
4. Homicide.
5. Staying at a friend's house.
6. He has run away and is loitering around the streets with the money he has.
7. Hiding in school.
8. Accidental death.
9. Hiding in LAN shops.
10. He has run away and is living with someone who has hired him for work.
11. His mother is lying.
12. His father has taken him back to China.
13. Some other thing.
14. A company has hired him for his outstanding talents in something, and he is happily overseas.

[EDIT: The answer was apparently 6. And half of 3. And possibly 9, but I don't know for sure.]
[But anyway: hurray]

-Zan