Once all 5 crime scenes are completed, you can go into your save game file and improve your score. Open the file in Notepad or a similar program. Scroll to the bottom of the page and the last few lines are your score and rating for each crime scene. For a perfect score set the following values:

evd = 100
hint = 0
ranking = 3
bonus = 10
score = 100

The last bonus should be 25. This will unlock the extra bonus pictures and animated story boards