Kenneth Park murdered his in-laws while sleepwalking.

On May 23rd, 1987, Kenneth Parks rose from his bed, wandered out of his home, drove 14 miles in his car to the neighbouring town, and proceeded to beat his mother-in-law to death and choke his father-in-law.

Covered in blood and bruises, Kenneth drove to a nearby police station and told the police, he “thought” he had murdered someone. A few hours later he identified the dead bodies of his in-laws. Confused Kenneth, told the investigators that it was “all his fault”.

Later, Kenneth’s defence in court claimed he was sleepwalking while committing the murder.

Sleepwalking has always been considered harmless, making for funny conversational anecdotes and humorous incidents for family gatherings or entertainment. Yet one would never imagine a quirky habit like sleepwalking transform into acts of violence in one’s sleep.

Nevertheless, for Parks, this small abnormality transformed his life forever.


Sleepwalking comes in many forms. In most cases, a sleepwalking person remains confined to their bed or room. And, is mildly aware of their surroundings, they can navigate their apartment with closed eyes, mostly due to habit and instinct. Furthermore, sleepwalking is usually non-violent, with two notable exceptions — Somnambulism and RBD. (RBD stands for REM Sleep Behaviour Disorder, and if you’re wondering what REM is, we’ll get to that in a bit).

These were the two possible sleep disorders that Kenneth suffered from, though very different, they both allow violence and coordinated actions like walking while holding a knife.

The type of aggression that Kenneth displayed is called Somnambulism.


In RBD a person is in the REM stage of the sleep cycle. REM stands for Rapid Eye movement, and this is a phase unique to mammals and birds. It's characterised by, well, a rapid movement of the eyes - but also activity in the brain which is similar to wakefulness. REM is the stage of sleep where the chances of dreaming are the highest, and REM dreams are also likely to be more vivid.

And then, there's the characteristic most important to us: partial paralysis. When we dream, our neurons are firing in a similar fashion to how they would if the dream were really happening. So if our arms and legs weren't paralysed, we'd end up acting out our dreams - which is exactly what happens during RBD.

A person who does not have partial sleep paralysis - as is the case with RBD patients - can physically act out their dream. They may thrash around violently in their sleep, as they mentally walk, run, and move through their dreamscape. But they could also wake up the moment they get up from bed and their feet hit the floor.


Somnambulism, on the other hand, happens in a stage of the sleep cycle when the person is in an extremely deep slumber. Any attempt to wake up the person would be ineffective, resulting in aggression and violence. The person might be able to navigate their surroundings due to habit but cannot perceive any signals or messages from their environment.

During sleepwalking, the regions responsible for the coordination and integration of information from the surroundings - the cerebral cortex and cerebrum - show no activity. So a sleepwalker has no consciousness: they cannot actively make decisions about where to go or whether to hurt someone or escape.

Somnambulism patients, cannot use their senses of vision, sight, smell etc to understand their environment and cannot form memories while asleep. It's equivalent to being in a coma - a vegetative state where the person goes through sleep cycles is alive but is not aware.


Many of the tasks we do in daily life, seem rather easy and simple. But was it always so? We all know a time when something as uncomplicated as reading time seemed like a Herculean task! Or, what about driving a car? Remembering all the different functions, and the numerous instructions sure isn’t an easy task, yet we have mastered it.

With practice, it becomes so deeply buried in your brain — so much that you’re not even conscious of it— that you can finally, well, drive in your sleep.


Kenneth’s defence in court was that while sleepwalking that night he was absolutely unaware of his actions. The actions had been performed by his body without his permission, they violated his self-control and free will. As per records, his wife claimed he had no intention to murder his in-laws, they had been supportive of him even though there was a lawsuit against him.

Kenneth’s response was probably out of extreme stress and fear because he had been accused of embezzlement and was going to be taken to court soon.

The biology of sleepwalking in this particular crime scene raises a lot of legal questions about what comprises a “murder”. As per Kenneth’s account of driving 14 miles and having little memory of the incident, he seemed to have somnambulism which allowed him to stay asleep for a long period. He was able to travel, murder his in-laws, wake up, and then go to the police.


While medically Kenneth was innocent of the crime, the court was still not convinced legally. Sleepwalking which involves violence and murder has huge legal ramifications, blurring the lines between law and medicine.

Most countries jurisdictions study two components of a crime: actus reus — which is the crime itself, and mens rea — the intent of the crime. If one component is absent the person is forgiven and acquitted of murder. In Kenneth’s case, he did not have criminal intent (mens rea).

For murders involving cases of consciousness and intention, the legal term used is automatisms. Neuropsychologist Peter Fenwick theorised that “an automatism is an involuntary piece of behaviour over which an individual has no control”. By this standing, Kenneth should have been acquitted since he did have a case of automatism.

He should have been acquitted, but there was a catchphrase…


Kenneth suffered from a sleepwalking disorder which in legal language is classified as insane automation. The two classifications of automatism are sane automatism and insane automatism.

Sane automation considers external factors — such as a blow to the head — where the person is not of sound mind in the act of crime and is immediately acquitted.

Insane automatisms consider internal factors — such as mental health, sanity, maybe even a brain tumour — and the person has to be sent to a psychiatric institution.

While traditionally sleepwalking may be considered insane automation, should someone actually be sent to a mental health ward? However, classifying sleepwalking as a sane automatism would be inaccurate.

This is where the lines begin blurring for law, biology, and ethics of the individual.


What does it mean to sleepwalk legally? How do we fairly convict Kenneth of the crime he committed unknowingly?

A brilliant research on Neuroethics reimagined the rules of automatisms to consider Kenneth’s narrative as a patient and murderer.

The author classifies Sleepwalking — Somnambulism as a Sane Automatism. After all, this disorder is not something that grows naturally within the body, it is influenced by external factors like perhaps drugs, extreme stress and anxiety.

The factors that influence this disorder has everything to do with the environment. And so, it’s considered to be a form of Sane Automatism.


But, wait a minute, if there is a family history of mental disorders this could be considered insane automation. It all depends on the variables, it could be sane or insane — it’s not black and white.

In the case of Kenneth, he had a sleepwalking issue since childhood. He should have taken the necessary precautions medical interventions and therapy in the time of stress to help him control any unwarranted outbursts. Still, the jurisdiction should have taken into account his mental instability, instead of accusing him of a murder he had committed unconsciously.


The depth of this case is a brilliant blur of the intersection of neuroscience and law. A person of strong moral ground and ethics may think it was right to convict him. While another might consider lessening his punishment an act of human charity towards a man who wasn’t even aware of his crime.

As Immanuel Kant said, “In law, a man is guilty if he violates the rights of others. In ethics, he is guilty if he only thinks of doing so.”

Kenneth Parks was charged with an attempt to murder, but acquitted of his crime. He is a special case because while he violated the rights of others,  he didn’t think of doing so.

As you can see, sleepwalking can turn dangerous — so let this be a wake-up call.