Deputy Marshal Max Clayton was a character introduced in Season Eight of DEXTER. He was a federal marshal who is informed by Private Investigator Jacob Elway that Hannah McKay is back in Miami, going under the alias 'Maggie Castner' (based on what Debra Morgan had told him earlier).
In pursuit of Hannah, he eventually comes to suspect that Dexter Morgan has resumed his relationship with her and the two are planning to leave Miami together. When he voices his suspicions to Debra, she immediately dismisses them (she is in fact, helping Dexter hide Hannah). However, after Harrison hurts himself while playing on Debra's treadmill, Hannah is forced to expose herself while taking him to the hospital (who at this point, can't get in touch with Dexter). A receptionist there recognizes her and soon informs Clayton that she was at the hospital with her "son". When Clayton sees the name 'Debra Morgan' written on the waiting list, he believes that Debra is harboring Hannah.When Debra is called by Dexter to the location where Oliver Saxon is being held captive by him, Clayton follows her and finds Saxon bound in The Treatment Room. In the pretense of an innocent victim, Saxon gets Clayton to free him, before stabbing him in the heart with one of Dexter's knives, killing him on the spot. He then takes Clayton's gun, and as Debra walks in to arrest him, he quickly shoots her in the stomach. She fires at him as he escapes and is able to maim his arm.