Why David Reid stabbed his parents to death in Sydney home

David Reid’s crime stands out as one of the most bizarre. But the neuropsychologist who assessed him has revealed his motive.

In a career of strange cases, the parricide of David Reid stands out as one of the most peculiar for Dr Susan Pulman.

What the forensic neuropsychologist found particularly puzzling was that there appeared to be no prior indication the 46-year-old software engineer could be capable of such violence.

But on a chilly morning on August 6, 2019, Reid dressed for work in the southern Sydney home he’d lived all his life with his parents, Diana, 71, and Graham, 75.

Then, he stabbed his mother to death as she ate breakfast, and turned the knife on his father as he lay in his bed.

He made no attempt to hide his crime, immediately phoning emergency services and telling the operator: “I stabbed my parents and tried to commit suicide”.

“If you’d looked at this man’s risk of committing a violent offence prior to killing his parents, you would say it was a very, very low risk. There was no indication. So it was very unusual in that regard,” Dr Pulman said.

The esteemed neuropsychologist was called to assess Reid in custody following the attack to provide a report to the court about his psychological state and mental health.

“His presentation when you interviewed him was very unusual. He was a very difficult case for psychiatrists to classify … this man does not present as your typical 46-47 year old man,” she said.

Indeed, the four mental health professionals who tendered reports during Reid’s court case were divided in their opinion. It was suggested he could have been suffering from an emerging psychotic illness, major depressive illness or even ADHD.

Dr Pulman, who has extensive experience working in the Children’s Court in child protection matters, came up with an alternate explanation. Over the seven hours she spent interviewing Reid, she noted he exhibited similar behaviours to those she had seen in children in child protection matters.

David Reid, 48, killed his parents at their Sydney residence.

“My own opinion in the matter was that this was a young boy probably who was quite socially awkward [and] extremely bright. There were two children in the family [and they were] being brought up in a very religious environment,” Dr Pulman said.

“Certainly his parents provided for him materially. He didn’t ever go hungry, he had everything that he needed and there was no physical abuse whatsoever. But he described to me a number of behaviours that raised alarm bells for me. It looked like from a very young age as what I would describe as emotional deprivation.

Dr Susan Pullman, who assessed David Reid. Picture: Sam Ruttyn

“This was a young boy who, from his description, was never really given a hug. He described to me that he was raised in an environment where you don’t express your feelings, we don’t acknowledge them, we don’t validate them.”

What Dr Pulman believes resulted is a young man who felt completely unloved and unacknowledged as an individual.

Graham and Diana Reid, who were tragically found dead in their Sutherland home in August 2019. Picture: Supplied

Of course, this is no justification for violence but Dr Pulman suggests the level of emotional deprivation may have created empathetic and emotional voids, meaning Reid was unable to function with his full capacity.

“If that’s the case, that he did not get the emotional reciprocity that a child needs when they’re growing up, their brain does develop differently. What happens with children that are in an emotionally deprived environment is the connections that develop in a young child’s brain that ignite feelings of empathy and understanding of emotion, those connections drop off. And they don’t then redevelop,” she said.

In May, 2021, Reid was sentenced to 10 years and six months with a non-parole period of five years and six months.

Although originally charged with murder, his charges were downgraded to manslaughter with the Crown accepting on the basis he was substantially impaired by an abnormality of mind.

“His presentation is so overwhelmingly flat and depressed when you talk to him, that it can be misinterpreted as him even having an intellectual disability because he’s so incredibly slow, when you ask him a question. And his profile when I tested him from a neuropsychological perspective was grossly impaired. He was incredibly intelligent, but [there were] clearly aspects of his brain functioning that was grossly impaired,” Dr Pulman said.

“I believe what was happening was he got to the stage where he could no longer control his despair in such a way that he lost control of his actions, and hence, a tragic event occurred and it was his intention to also take his own life as well.”