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March 23, 2026
By: Adam J. Poteracki

When Estate Planning Meets a Murder Mystery

Few things create more tension than a surprising estate plan. In the hit film Knives Out, the unexpected reading of a will turns a wealthy family against one another and raises an important legal question: what happens if someone who stands to inherit is responsible for the decedent’s death?

While most families won’t face circumstances as dramatic as those surrounding Harlan Thrombey and his heirs, the legal issue at the heart of the story is very real.

SPOILER ALERT: The discussion below reveals major plot points in Knives Out. If you have not seen the film and want to preserve the mystery, you may want to pause your reading for a moment to watch the film and then return for fascinating legal analysis.

Early in the film, Harlan’s nurse, Marta Cabrera believes that she accidentally administered a lethal morphine overdose to Harlan. To protect her from prosecution, Harlan devises a plan and ultimately takes his own life, staging the scene as a suicide.
Later, we learn that the overdose was never real. Harlan’s medications had been switched by his grandson, Ransom Drysdale, who intended to frame Marta so that she would be convicted and disqualified from inheriting from Harlan. His ultimate goal: regain access to the fortune he expected to inherit.
Illinois, like many other states, includes what is commonly referred to as the “Slayer Statute” (755 ILCS 5/2-6). In simple terms, if someone “intentionally and unjustifiably” causes another person’s death, they cannot inherit from that person.
This rule applies to wills, trusts, life insurance, joint accounts, and any other benefit that arises because of death. If the Slayer Statute applies, the law treats the wrongdoer as having died before the deceased person, and the wrongdoer receives nothing. Importantly, a criminal conviction is not required. A probate court can make its own determination using a lower civil standard of proof.
So how would the “Slayer Statute” be applied to Marta? At first glance, Marta appears responsible for administering the fatal dose. But two key facts matter:

1. She did not act intentionally. She believed she was administering the correct medication.

2. The dosage was not actually lethal. The labels were switched, but she selected the correct drug based on her training and experience.

Ransom’s actions are more complicated. He intentionally switched the medication labels, believing this would cause Harlan’s death and lead to Marta’s prosecution. While he did not physically kill Harlan, his scheme set the chain of events in motion.
An Illinois court would likely consider intent, causation, and foreseeability. Ransom clearly intended to cause death or serious harm to Harlan to secure his own financial gain. His conduct directly led to Harlan’s belief that he would die, prompting the suicide. It was also reasonably foreseeable that switching the medications could result in death.
Illinois courts do not require the wrongdoer to wield the weapon personally. If intentional misconduct proximately causes the death, the Slayer Statute can apply.
Under these facts, an Illinois probate court could find that Ransom “intentionally and unjustifiably” caused Harlan’s death and therefore treat him as having predeceased Harlan—meaning he would receive nothing from the estate, even if he had been included in Harlan’s will.
While most estates do not involve elaborate murder plots, the legal principle is real and important: a person who intentionally and unjustifiably causes the death of another is barred from receiving any property or benefit flowing from the decedent’s death.
Clear estate planning cannot eliminate all family conflict, but it can strengthen the enforceability of your wishes. If you have questions about your estate plan or beneficiary designations, your Robbins DiMonte attorney is here to help ensure your legacy unfolds with far less drama than a Hollywood mystery.