No Ordinary Search - Jennifer A. Brown - Bog

A planned terrorist attack at The Chester City Mall left several dead, injured, or with traumatic memories of the event ten years ago. Kyle Manning is no exception to this. His sister Becca, who turned up missing, reappeared briefly during Black Friday while he was broadcasting live from the complex, only to be killed soon after.
Now, ten years later he is back to film a documentary about the event, in the hopes of closure. In the process, he encounters a group of street kids who are searching for the elusive million-dollar prize rumored to still be hidden in the mall, from a scavenger hunt taking place that day. He and his partner, Scott Reynolds end up blackmailed into not reporting them for being there, until a journal is found in one of the abandoned stores. Kyle immediately recognizes the handwriting as his sister's and vows to get to the bottom of the ultimate question - why a journal was there dated after Becca was killed, in her handwriting - which details finding the money inside the mall before the street gang even set out to look.
After exhuming the body, it is discovered it is that of a missing teen from Kingsridge, Stephanie Lanham. When a photo resurfaces on Facebook, incriminating Scott in Lanham's disappearance all eyes are on him as the secrets from the past come to light.