Here is the full list of all 19 Sixth Grade Detective achievements.
Finish the game without lying.
Destroy the mean notebook once and for all.
Finish the game without attempting to blackmail anyone.
Start a romance.
Find Red Lightning.
Follow the clues to your birthday present.
Find the source of the mean rumors.
Help Evan come clean about his makeover business.
Accuse the right person of stealing Shashi's books.
Find a bike.
Get a book on codes and ciphers.
Get some fingerprint powder.
Get a pair of binoculars.
Play Swords and Sorcerors.
Get a makeover.
Publish an article in the school newspaper.
Figure out the identity of your secret admirer before the dance.
Start multiple romances at the same time.
Buy your very own bike!