The "Unknown Subject" (UnSub) is identified as , a local FBI agent and family friend who was part of the investigative team.
: He exhibits narcissistic traits, an inflated sense of self-worth, and a specific "delusion of eloquence," where he uses overly formal language and avoids contractions to appear more intelligent. [S1E5] Broken Mirror
: Gideon realizes Shyer is the kidnapper after noticing he called Mr. Davenport by his first name—a sign of social familiarity that most local agents didn't have. The team eventually tracks Shyer to his hideout to rescue Trish. Production Notes The "Unknown Subject" (UnSub) is identified as ,
: Jason Gideon uses an "unusual tactic" during a phone call, hanging up on the UnSub repeatedly to assert dominance and provoke a reaction that reveals Shyer's personality. an inflated sense of self-worth