It is mentioned that Brouchard has been wearing a pouch with Maddie's hair in it around his neck ever since he was arrested. However this is not something he would have been allowed to keep, anything like that would have been confiscated as evidence. Plus even if it wasn't considered evidence he still would not have been allowed to wear it while in jail, inmates aren't allowed to keep personal items like that; especially since the pouch's leather straps could easily be used as a weapon to choke someone.