The figure’s slender body and quiet demeanor heavily implies that Rodrigo’s killer is the same person who killed Matt Butler (and, likely, Haley Whitehall, too). When Rodrigo’s text elicits a ding from the killer’s phone, it suggests that the killer is one of Rodrigo’s friends—possibly David Ware, as Rodrigo apparently suspects. That someone so close to Rodrigo would kill Rodrigo—without Rodrigo suspecting it up to the end—reinforces the idea that people are inherently unknowable.