It ends with us

She regretted picking criminology after that.
***
One day, the smell of blood reels Bianca towards the dead body of her classmate, her best friend, Anabelle. The next day, the topic of the criminology lesson was about the murder case about Anabelle. The class was told that if any students wanted to work on it, they should sign up. After all, they needed all the help they could get. Bianca was the only one that did.
Now, her professor, Mr.Bennet, and her are working on the case together. At the end, all clues trace back to one person she knew very well...
But, who is the murderer? And does she remain alive afterwards? Or does she kill herself before answers emerge?