Criminal Minds Wiki

Mark Henshaw is a poisoner, and "wound collector"-type spree killer and stalker-turned-mass murderer who appears in the Season Thirteen episode of Criminal Minds, "All You Can Eat".


Mark worked at his parents' restaurant, which was named after the family surname, as a cook. The restaurant proved to be very successful as Mark's parents were very kind to their customers and offered free meals to anyone who was down on their luck. While working at the restaurant as a cook, Mark suffered second-degree burns on his right hand after a pot of boiling water tipped over. On July 16, 2017, his mother died of a stroke and two weeks prior to the episode, his father died of a heart attack. His parents' deaths resulted in fewer people coming in. The restaurant was shut down and became a buffet named the Good Eatin' Buffet. The deaths of his parents and the perceived betrayal by the former customers of his family's restaurant caused Mark to snap and start killing people with rat poison, which he had already been buying for the restaurant to kill any rats that got into it. He first killed Serena Logan, who approved the loan for the buffet, then killed Clayton Osborne, who wrote a negative online review of Mark's family restaurant that went viral. This led the CDC to call in the BAU, as they had believed Mark's killings to be the work of a bio-terrorist.

All You Can Eat

After Mark poisons Serena Logan and Clayton Osborne, the CDC call the BAU to assist in the investigation in what they believed was an act of bio-terrorism. The next day, Mark arrives at a business conference where he laces the food and drinks with rat poison, resulting in the deaths of ten people. As the BAU presents their profile following the mass poisoning, Mark prepares for his attack on the buffett that replaced his family's restaurant. On the following day, Mark appears in the kitchen of the Good Eatn' Buffet and attends a meeting with the other chefs to prepare for the opening day. He sees this as an opportunity to increase the number of fatalities by adding the rat poison he brought with him to the food in the buffet area. When a customer asks him why he is spraying the salad, Mark states that he was wanting to ensure that the salad was fresh. Before his plan is set in motion, the BAU arrives and warns everyone not to eat the food. Mark tries to flee through the kitchen, but is dispatched and placed under arrest. Mark was later incarcerated for his crimes.

Modus Operandi

"Helps keep the food fresh."

Mark initially targeted one victim at a time, but later went after multiple victims at once. He killed his victims with rat poison which he kept in vials and put into food his victims were going to eat without anyone noticing. His first two victims were also stalked, allowing him to know where they ate. The victims would bleed out from the orifices of their heads as a result of ingesting the poison and lose half of their blood volume. During his attempted attack on the Good Eatin' Buffet, Mark had sprayed the poison onto the food in the display counters with a spray bottle (since the food was solid and therefore would not be able to mix with the poison), allowing for a great number of fatalities, but was stopped by the BAU before anyone could eat the contaminated food.


The unsub is hoping to inflict as much fear and damage as possible on Arlington's business community. His victims and their businesses symbolize wealth, success, growth, and development, all things he may feel are out of his reach. He derives pleasure in knowing that his victims are experiencing a cruel and painful death and that his crimes may create widespread panic. Those who poison, such as the unsub, tend to be non-confrontational, bottling up inside what they deem to be injustices. They use these imagined slights as justification to harm their victims. Lacking empathy with an exaggerated sense of entitlement, a poisoner cares only about their own wants or needs, which would explain the indifferent and heartless nature of these crimes. Poisoners believe their calculated plans, their cleverness allow them to kill and walk away and he has been able to do that, so far The unsub uses food as a method to mask the rat poisoning. He might be comfortable doing this because he works in the food industry. There's no indication he'll stop, and his next target could be even larger: a food festival, a supermarket, or even a school cafeteria.

Known Victims

  • 2018: Arlington, Virginia
    • April 9: Serena Logan
    • April 10: Clayton Osborne
    • April 11: The Arlington Business League massacre:
      • Alex Murazaki
      • Amy Piebons
      • George Pugilese
      • Kelly Sheldon
      • Christopher Thorton
      • Erol Finbart
      • Jillian Jagr
      • Rosalind Meryll
      • Sally Bison
      • Kim Anganraso
      • Chairperson Pam Chapman (attempted)
      • Multiple unnamed guests (attempted)
    • April 12: The attempted mass poisoning at the Good Eatin' Buffet
      • Multiple unnamed customers (attempted)


  • Mark is similar to Larry Feretich ("Brothers Hotchner") - Both are poisoners and one-time mass murderers who initially killed one victim at a time before committing a mass murder, had stressors that involved the deaths of at least one of their family members, killed one of their victims out of revenge, and had body counts in the double-digits. Additionally, both men used a poison that caused their victims to bleed from their faces.
  • Mark Henshaw is the last of only eleven serial killers in the show's history to have killed at least a dozen victims, yet not be a prolific killer because the span of their crimes was less than three years. The others are: