Found: Mystery/Suspense/Thriller “madox”

YA young detective
Likes to solve unsolved cases from FBI
Lives with her father I believe
Meets 2 guys on internet to help solve case
Meets them through Reddit ( I believe)
One of the guys name she meets is Madox
All 3 of them try to solve the case
Killer goes for blonde hair blue eyes
Killer always breaks the victims pelvis and dismembers body

The Amateurs by Sara Shepard?

>2 MissSquish: Yes! Oml thank you so much I’ve been looking for this book for years !