Michael Morgenstern, MD
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Michael Morgenstern, MD

About the author: Dr. Michael Morgenstern is double board certified in Neurology and Sleep Medicine and the founder of the American Sleep Apnea Society. He is the Director of the Morgenstern Medical in Lake Success, NY, where he treats patients with sleep disorders and other neurological conditions.
Michael Morgenstern, MD
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“I think I have killed some people” Mr. Kenneth Parks told police on May 23rd 1987. His hands were covered in blood. Earlier that morning the man described by his mother-in-law as “a gentle giant” repeatedly stabbed her body with a kitchen knife, brutally murdering her. The night before he went to bed like any other night. But about two hours later  he arose from bed and drove 15 miles prior to committing murder. He then drove to the police station. In a state of shock and confusion and covered in blood, he confessed to having done something terrible. Mr. Parks was not the only one shocked. So was anyone who knew Mr. Parks. He had no prior criminal record and was known for being a kind and passive person.  How could someone like Mr. Parks do this?


homicidal somnambulism-killing during sleepHis attorneys put on a novel defense at trial. They claimed that the entire course of events transpired while Mr. Parks was sleeping.  That Mr. Parks had committed murder while sleepwalking. Experts testified that a sleepwalker could perform murder without ever having planned to do so. It was possible that Mr. Parks could have stabbed someone not appreciating what he was doing and lacking any sense of control to stop the murderous actions.


On May 25, 1988, Mr. Parks was found not guilty.  His actions were believed to be performed by him during sleep, though, he lacked awareness of what he was doing . Instead, he was exhibiting automatic behavior that he couldn’t possibly control. Mr. Parks case was strengthened by several factors. He had a history of sleep walking.  Once, as a child, he almost walked out an open window, but was caught by his brother before it was too late. Then there was objective evidence from a sleep study showing findings consistent with sleepwalking. The timing of events also took place during the time of night when parasomnias, like sleepwalking, typically occur. Further, the circumstantial evidence did not add up to intentional murder. Mr. Parks was close with his mother-in-law. There were no motives uncovered during investigation, nor was there any attempted cover up.

Homicidal somnambulism

“Homicidal somnambulism” is murder that takes place during sleepwalking. Like sleepwalking, it is considered a parasomnia or an abnormal behavior that takes place during sleep. Sleepwalking (aka somnambulism) usually originates during the most deep sleep. Individuals enter into an incomplete state between normal sleep and wake. It is like their body is awake but their brain is asleep. They may open there eyes, walk, eat and perform other complex behaviors that resemble people that are awake. Sleepwalkers have no recall of any of the events that take place during the night. Electroencephelogram (EEG), which shows electrical activity in the brain, performed on sleepwalkers demonstrates that they are still sleeping even when their eyes are wide open or when they are performing other behaviors.


Sleepwalking may occur in about 15% of children and 4% of adults. Most sleep walkers don’t exhibit such complex motor activity as did Mr. Parks. Generally,  they perform simple activities such as walking purposelessly or talking nonsensically. For example, sleepwalkers can usually turn a door knob, but may have difficulty opening a lock. Events usually take place in the first half of the night, when there are higher levels of deep, slow wave sleep. Sleepwalkers tend to have abnormally high levels of deep sleep as well as disruptions of slow wave sleep evidenced on EEG.* Treatment with behavioral steps such as avoiding sleep deprivation, minimizing sleep disruption (e.g. TV, loud noises) and safety proofing a home or bedroom are usually sufficient to manage sleepwalking. Sleep disorders such as sleep apnea can also disrupt sleep and trigger parasomnias. Therefore, sleep studies may be indicated to rule out disorders such as sleep apnea. If sleep apnea is found to be a culprit, the parasomnias may resolve upon treating the OSA and thereby minimizing the cause of sleep disruptions. Medications that reduce slow wave sleep may also be effective in more severe cases that don’t respond to other treatment.

History of homicidal somnambulism

With only several cases of homicidal somnambulism ever recorded, the chances of getting hit by lightning is probably a million times more likely.  Still, Mr. Parks actions were not the only recorded case. Several episodes from the middle ages to date have been attributed to sleep disorders. They include reports such as that of Bernard Schedmaizig, who chopped up his wife with an axe during sleep; An officer that shot a patrolling guardsman and his horse; A servant who murdered her master’s child by stabbing;  A housewife that threw her infant out a window; A father who banged his infants head on the floor until crushing his skull, and; A fireman who attempted suicide after waking up to find he had mangled his wife’s cranium with a shovel. In all of these cases, murder was believed to take place during sleep.

Sleepwalking related murder is unlikely but not impossible. It is plausible as was found in the trial of Mr. Parks as well as on an appeal that came before the Supreme Court of Canada who upheld the verdict. Doctors who were asked to evaluate Mr. Parks were initially skeptical but eventually became convinced that homicidal somnambulism, though rare, is a real parasomnia.


[* Other findings on EEG in sleepwalkers include: hypersynchronous delta, frequent SWS-wake transitions and microarousals following delta waves.]

Homicidal somnambulism Sources:

1. https://sleepfoundation.org/sleep-disorders-problems/abnormal-sleep-behaviors/sleepwalking
2. http://www.aasmnet.org/Resources/FactSheets/SleepwalkingTalking.pdf
3. https://en.wikipedia.org/wiki/Homicidal_sleepwalking
4. http://www.lakesidepress.com/pulmonary/Sleep/sleep-murder.htm
5. Broughton, R., et al. “Homicidal somnambulism: a case report.” Sleep 17.3 (1994): 253-264.
6. Image: Sleepwalker. M Pirner.

About the author: Dr. Michael Morgenstern is a board certified Neurologist, expert in Sleep Medicine and  founder of the American Sleep Apnea Society. He is Director of the Cedarhurst Sleep Center in Long Island, New York and also sees patients with neurologic conditions.