The terrifying consequences of sleepwalking: Sleep scientist recalls terrifying 1988 case of a man who drove his car and murdered his mother-in-law without waking

A sleep scientist spoke about a bizarre sleepwalking case which saw a man drive miles to his mother-in-law's house to murder her - but he was found not guilty.

Professor Guy Leschziner, a world-renowned expert in Neurology and Sleep Medicine, appeared on Dragons' Den star Steven Bartlett's The Diary of a CEO podcast to speak about sleep disorders and how sleepwalking can be used as a defence in a court of law.   

The most notorious case occurred in Canada in 1988, when 23-year-old Toronto man Kenneth Parks, was acquitted of murder and attempted murder of his parents in-law.

In the early hours of May 23, 1987, he drove 23km to their house, broke in, assaulted his father-in-law, Denis, and stabbed his mother-in-law Barbara Woods, 42, to death.

Parks, who had gambling debts, claimed he was asleep the whole time and was not aware of what he was doing. 

The most notorious sleepwalking case occurred in Canada in 1988, when 23-year-old Toronto man Kenneth Parks, (centre) was acquitted of murder and attempted murder of his parents in-law

Professor Guy Leschziner (pictured) speaking on The Diary of a CEO podcast, where he talked about bizarre instances of sleepwalking, including where people had murdered while in slumber

Leschziner said: 'Apparently in his sleep he drove several miles to his parents in-law's house and apparently got a tire iron out of the boot of his car and bludgeoned his mother-in-law to death.

'Then tried to kill his father-in-law and ended up throwing him into a swimming pool, now this was made even more curious by the fact that there had been some evidence that he'd been having some financial difficulties and had some discussions with his parents-in-law about about financial issues, but it was deemed by a court of law that this happened whilst he was sleepwalking.

'He was actually acquitted, so this is a remarkable story, now is it impossible for somebody to drive in their sleep? No, I've seen it myself, but it seems like stretching credibility that somebody could have undertaken all of that whilst sleeping, but in the court of law he was found not guilty.'

Defense attorney Marlys Edwardh said that on the night of the killing, Parks 'plunged into a deep, deep sleep. His next memory is seeing his mother-in-law's face.'' 

The attorney said he then regained consciousness, fled the house and drove to a nearby police station.

Bob Adair of the Toronto police homicide squad testified Parks said he had no idea how he got to his in-laws' home and told officers he had no reason to harm them.

Leschziner revealed that although driving in your sleep is uncommon, it does happen, and he has a patient who has experienced it on numerous occasions. 

In the early hours of May 23, 1987, he drove 23km to their house, broke in, assaulted his father-in-law, Denis, and stabbed his mother-in-law Barbara Woods, 42, to death

Leschziner is a world-renowned expert in Neurology and Sleep Medicine and was the latest guest on Dragons' Den star Steven Bartlett's (pictured) The Diary of a CEO podcast

He said: 'I've got a patient, who I don't see anymore, who I mentioned in my book. She has driven several miles in her sleep, and in fact has driven a motorbike in her youth in her sleep and the only knowledge that she had, was her landlady at the time said ''where were you going at 1:00 in the morning clutching your motorcycle helmet''.

'She'd obviously been for a ride in the middle of the night without any recollection.'

The professor said in those kinds of situations it's likely that the majority of the brain is 'probably awake' because it's hard to envisage how somebody could carry out complicated tasks if the majority of their brain was asleep.

Leschziner revealed he has seen many people commit crimes in their sleep and some have been convicted.'    

He said: 'I was involved with somebody who shot a family member in their sleep. I've seen individuals who have committed sexual assault in their sleep. Somebody who was convicted for rape as a result of a sleep disorder.'

Speaking about how sleep disorders are examined in court after a serious crime has been committed, the professor said: 'First of all, is past behavior consistent with what has happened on that night in question.

'Secondly are there any features about the event itself that suggests that there was an attempt to cover it up, or a degree of pre-planning in order to commit that particular act.

'Also whether or not there can be evidence found by studying that individual's sleep, that they suffer from these kinds of sleep disorders.'