This explains a lot. Why Pip took to pursue the Bell Disappearance Case for her project? So Pip and her gang of friends (6 in total) are celebrating the end of term by playing Kill Joy - a murder mystery game. Every friend is a character from the story and the story slowly unfolds as the game progresses. There are clues, witnesses, backstory, motives and what not are presented. Each character defends himself/herself and provides an explanation. At the end the culprit is revealed.
But the solution provided by the game-makers is just too simple. It doesn't account for many finer details in the game. Pip, on her notepad, has accounted for every detail and proposes a completely different, mind-boggling, out of the earth explanation for the series of events which does infact fit in. She's all angry that a series of such complicated events cannot have a simple solution. And this reminds her of the 5 year old events that took place in her town. The events were complicated but the explanation provided by the police was too simple. That's the reason she chooses that topic for her Capstone Project.
It is a short prequel to the book series but amazing none the less. And it explains the things like her decision for the project and her relationship with Jamie.