It should've be a 2-part Law & Order SVU episode. In fact, there are better SVU episodes than this.
SPOILERS:
Lazy crime writing...a girl suddenly decides to come forward and tell her story from LAST APRIL when she was almost murdered in the blue van - partial license plate - winston cigs? She remembered all these details and didn't file a police report? She didn't come forward when it happened which was around the same time that Katie went missing? Of course not, because that would've solved the case immediately and there'd be no show.
The ex-cop suddenly decides to come forward WEEKS LATER about his gun being missing the night of a highly publicized murder? And he didn't even check his security cameras right away to see who took it? Of course not, because that would've solved the case immediately and there'd be no show.
So many ridiculous, non-sensical, and unnecessary plot points - too many to mention.
If you want to see an amazing detective story, watch "Unbelievable" on Netflix.