This story features a teen amateur sleuth, high school senior Pip, who isn't convinced -- unlike the rest of the small town where she lives -- that a teen boy who committed suicide over his girlfriend's murder five years ago did either the murder or committed suicide.
Pip investigates the murder of Andie Bell, popular high school senior, closet drug-dealer, kinda-sorta girlfriend to Sal Singh (her supposed murderer), and all-around terrible sister, for her high school senior project. Pip's primary ally: Ravi, Sal's (handsome!) younger brother.
In the process, Pip does a lot of Nancy Drew-ish type stuff, extra-legal shenanigans such as impersonating people via text and phone to obtain information or coerce confessions of facts, to get to the bottom of where Bell and Singh went on the night Bell was murdered.
Pip can do all of this because Fairview has a stereotypically small and inept police force, which never hinders her efforts or even catches on that she's investigating, and left plenty of clues for her to discover, such as 5-year-old pictures still posted to private social media accounts the police were just too dumb (i.e. too old to know about) to search.
I won't ruin any of the twists; I'll stop here. Read it to find out how it unfolds. Enjoy!