"Gentleman cambrioleur"

This is a hideout of a criminal — but he already ran away.

After some time of profiling, the policeman finally drew a conclusion:
"This criminal must be a [ ? ]"

Answer:

*The original version (Japanese) was made by Nao Fénix.

The answer is a single word with less than six letters.
It doesn't mention nationality or gender.

I'm not sure whether this profiling is really helpful
(or rather, I am sure it isn't)...