Who is Brad Bartlett from The Rag and Bone Shop and what is their importance?

Brad Bartlett is Alicia's twelve-year-old brother. He is an athlete at Monument Middle School, and he is one of Jason's classmates. Brad is swimming in the Bartlett pool on the day of his sister's murder, and he uses his friends as his alibi for her time of death. When his alibi falls apart, however, Brad confesses to murdering his sister.