The cache is not at the posted coordinates. There is no need to visit the posted coordinates.
Solve the mystery and you will get the coordinates of a geocache.
Once at the cache location, you have to solve a field puzzle to open the cache container to sign the log and to be able to claim the find.
Difficulty:
* Prerequisite: 5
* Puzzle: 1
* Field puzzle: 2
* Hide: 2
Hi, I am Inspector Cachet and I am here to help you with your detective skills. 
Hard work deserves a reward. This is your reward for finding the other caches in this series. But I couldn't help myself and there is still a field puzzle to solve before you can claim that smiley.
The puzzle
Each cache has a codeword inside its logbook. Put the words in alphabetical order and you will be rewarded with the location of this bonus cache. Spaces are ignored by the checker.
The following caches contain a keyword in the log book:
GCARDW4
GCARDW5
GCARDW6
GCARDWA
GCARDWB
You can validate your puzzle solution with
certitude.
Important detail: Once you find the cache, you will need some additional information to open the container. The puzzle is to combine knowledge from the other caches in this series to open the container and claim the smiley.