Here is the full list of all 9 Detective Grimoire achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Full suspicion on the culprit, none on anyone else
Complete the game
Finish speaking to the Little Girl
Complete the game 100%
Read the letters on Remington's desk
Draw a cute ghost in your notebook
Examine all the Boggy merchandise
Get inside the tent
Examine the crime scene