YMMV / Person of Interest S02 E17

• Complete Monster: Alex Declan kills his victims and steals their identities. After recently murdering Special Agent Alan Fahey, his eighth victim, he steals his identity as well and later assists Finch and Reese in trying to uncover the killer on Owen Island to divert any suspicion from himself. During the investigation, Declan murders the island's deputy, framing a Marine in the process and endangering several civilians. When Finch discovers that Declan is the imposter, Declan takes Finch hostage and attempts to murder him so he can steal his identity like he did his other victims. Although Declan believes the identities he stole were being "wasted" and that he "did them justice", Finch ultimately deduces that he kills people because he enjoys it.