The Trinity Killer
Character Profile
Portrayed By
John Lithgow
First Appearance
Living the Dream
Last Appearance
The Getaway
Full Name
Arthur Mitchell
The Trinity Killer
Alan (to Tarla Grant)
Manner of Death
Killed by Dexter Morgan
60 (at death)
Personal Status
Marital Status
Sally Mitchell (deceased)
Immediate Relatives
Henry Mitchell (father; deceased)
Marsha Mitchell (mother; deceased)
Vera Mitchell (sister; deceased)
Christine Hill (daughter; deceased)
Jonah Mitchell (son)
Becca Mitchell (daughter; deceased)
Professional Status
College Tutor
Volunteer for Four Walls One Heart

Church deacon
Serial Killer

Killer Profile
"The Trinity Killer"
Number of Victims
At least 122
Modus Operandi
Straight razor, hammer (or another weapon capable of bludgeoning)
Killing Method
Child Murders: Each boy is subdued, held captive for several days before being sedated and buried alive in concrete.

Bathtub Murders: Mitchell subdues the woman, removes her clothes, takes her into a bath with him before incising her femoral artery with straight razor. Death by exsanguination.

Jumper Murders: Mitchell verbally forces a woman to jump from a ledge.

Bludgeoning Murders: Using any one of a number of blunt instruments, Mitchell repeatedly bludgeons a man's head.

Method of Disposal
Mitchell does not dispose of the bodies for the bathtub, 'suicide' or bludgeoning murders. He does, however, bury alive the ten-year-old boy.
At a young age, Mitchell witnessed his sister die in the shower (implied to be his fault, albeit indirectly). His mother then committed suicide and his father was bludgeoned outside a bar.
For the character behind the serial killer, visit Arthur Mitchell.

The Trinity Killer is a character in Season 4 of DEXTER.

Trinity is a serial Killer who, for thirty years, has killed in yearly cycles of three victims. In this order, he cuts the femoral artery of a young woman in a bathtub, coerces a middle-aged mother to jump to her death, and bludgeons a middle-aged father. Later, it is discovered that he actually kills in cycles of four. The first victim is always a ten-year-old boy who is sedated and buried alive in cement.

Trinity is thought to be a lone-wolf by Special Agent Frank Lundy. However, as Dexter Morgan stalks him, he realizes that Trinity has a family. In trying to overcome his marital problems with Rita, Dexter befriends Trinity to learn how he balances his family life with his secret life as a heinous killer. In time, he realizes that Trinity is abusive and controlling, as both a father and a husband. Thus, he is able to pursue his extra-curricular activities (since his family does not have to deal with his abuse during his absences). Dexter feels that he could never be a monster to his family like Trinity and comes to despise him, rather than look up to him. Dexter eventually kills Trinity, but his previous reluctance to kill him, when he had several opportunities to do so, lead to his wife's death by Trinity's hands.

Named Victims

Young Boys:


  • Vicky Noonan
  • J. Lewitt - 3/12/1993
  • I. Rosengard - 9/5/1994
  • A. Darakjan - 2/26/1995
  • Loretta Kellerman
  • M. Bogert - 9/16/1997
  • L. Candace - 8/23/1998
  • J. Spaan - 3/9/1999
  • H. Grodman - 10/7/1999
  • Anita Soloman
  • L. Fisher - 5/11/2001
  • R. Goldman - 10/24/2002
  • K. Watkins - 4/15/2003
  • A. Goff - 5/11/2005
  • J. Meltzer - 9/18/2006
  • R. Cornelius - 7/20/2007
  • Tamera Klaman
  • L. Spheeris - 7/20/2008
  • Julie Hillard - 9/20/2008
  • Lisa Bell - 9/21/2009


  • D. Webster - 3/17/1993
  • E. Hemming - 9/10/1994
  • N. Reiss - 3/3/1995
  • J. Snisse - 9/21/1997
  • R. Elliot - 8/28/1998
  • R. Golden - 3/14/1999
  • C. Endless - 10/14/1999
  • P. Ford - 5/16/2001
  • J. Lewis - 10/29/2002
  • A. Asarcca - 4/20/2003
  • L. Pickford - 5/16/2005
  • J. Antonoff - 9/23/2006
  • R. Hermosillo - 7/25/2007
  • J. Leiberman - 7/25/2008
  • Tarla Grant - 9/26/2009


  • S. Hunter - 3/22/1993
  • J. Roberson - 9/15/1994
  • D. Freiburn - 3/8/1995
  • E. Newman - 9/26/1997
  • R. Dermott - 9/2/1998
  • B. Ball - 3/19/1999
  • F. Calvert - 10/19/1999
  • A. Severse - 5/21/2001
  • C. Moreno - 11/3/2002
  • J. Jones - 4/25/2003
  • A. Roman - 5/21/2005
  • J. Ellis - 9/28/2006
  • B. Polaski - 7/30/2007
  • R. Bear - 7/30/2008
  • Earl Doorman - 10/1/2009

Other Victims

The following victims are the few kills that Arthur has made outside of his kill cycle.

  • Henry Mitchell - Arthur's father. Though it is never confirmed, it is possible, due to the things he shouts at his later bludgeon victims. It is possible that Henry was Arthur's first kill, prior to the cycle.
  • Kyle Butler - Another bludgeon victim that he killed while he was trying to find Dexter. This one was done after he had failed at starting a new cycle. This man doesn't fit into Trinity's cycle because Arthur just wanted to kill him to silence him.
  • Rita Morgan - A bathtub victim. She is considered outside of his cycle for two reasons: He had yet to succeed in burying a young boy in cement, and she didn't fit the normal characteristics of his bathtub victims.

Attempted Victims

Alleged Victims

  • Frank Lundy - He was believed for some time to be a victim of Trinity, until it was confirmed that the person who shot Lundy and Debra Morgan was shorter than Trinity.
  • Rebecca Mitchell - She actually committed suicide in a bathtub, although Debra thought that Trinity was the one to blame.
  • Sally Mitchell - She was killed by Jonah Mitchell, but Debra also believed her to be a victim of Trinity.

Related Pages