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What Is The Criminal Psychology of Poisonings? A Forensic Psychology Podcast Episode.


what is the criminal psychology of poisonings, a forensic psychology podcast episode

With this podcast occasionally looking at forensic psychology, I really wanted to get a better understanding of poisonings. There are so many different types of poisons in the world from synthetic to natural to poisons made up of two or more components to become deadly (called duo-poisons). However, it still doesn’t explain why some people decide to use poisoning as their method of murder, so that’s the focus of today’s forensic psychology podcast episode.


Today’s episode has been sponsored by Forensic Psychology Collection. Available from all major eBook retailers and you can order the paperback and hardback copies from Amazon, your local bookstore and local library, if you request it. And Bettie Private Eye Mysteries Kickstarter includes a gripping private eye mystery about poisonings. Only available until the 28th July 2022.


What Is The Criminal Psychology of Poisoning?

There have been a lot of famous cases involving poisonings in the past and poisoning people definitely isn’t a new way to kill people. For example, healthcare killers like Harold Shipman, tend to overdose their victims on medication. As well as in 1993 Glenn Turner named his wife to be the sole beneficiary on his life insurance policy, so she killed him, made it look like natural causes and it wasn’t until she killed her second husband and their mothers got suspicious that she was investigated.


Leading Dr Michael Farrel to write his book called the “Criminology of Homicidal Poisonings”. Which Dr Farrel was in a good position to write because he’s a private consultant on the use of poison in murders, as well as he has a substantial background in medical research and psychiatry, with his book linking research in the fields of forensic toxicology with criminology.

And the text makes a solid contribution to both of these fields.


Additionally, I want to highlight why this is important to look at on a psychology podcast. Since one of the many things I absolutely love about psychology is that anything to do with human behaviour is under our remit. As psychology people we are within our right to investigate all aspects of behaviour, and poisoning someone is a behaviour, and poisoning is a type of crime, which again is a behaviour. Therefore, as these two are behaviours, we get to study them in psychology. Hence why I’m talking about it on a psychology podcast.


Furthermore, Dr Farrel goes beyond simply describing how murderous poisonings fit with the most popular criminological theories as to why people kill, but he also examines the deadliness and nature of different poisons, provides a history, identifies trends in poisonings and shows offender traits and victim characteristics.


Of course, as we know from forensic psychology, we always need to be wary of these offender traits and victim characteristics because they can be inaccurate and just plain unhelpful. But it is still “good” to make a reference at the very least.


Then Dr Farrel also discusses issues for prosecutors and investigators taking a poisoning case to trial.


The Criminal Psychology of Poisoners:

However, what is really interested to this podcast is that poisoners actually have a lot on their side when they poison someone. Since case reconstruction often depends on largely circumstantial evidence with an emphasis on the killer’s motive.


For example, Kristin Rossum was having an affair and her husband supposedly died of a fentanyl overdose because she wanted everyone to believe he had committed suicide. But he was very well known to be averse to taking pills and the suicidal note and rose petals Kristin had left behind made no sense.


Then after years of family members protesting the police and getting the police to admit their errors. The investigators finally decided that something was wrong because if she hadn’t leave the suicide note and the rose petals. Then there is a chance she could have been more successful as the investigators might have decided with her husband being in such a state, he might have overcome his aversion to pills. I don’t know but it is just a point showing how badly these case reconstructions rely on circumstantial evidence that isn’t always present. I’m just glad that for the sake of Kristin’s husband there was this type of evidence left behind.


In addition, and much more interestingly, many poisonings actually look natural or accident at first, or they can be passed off as suicide. Yet if the circumstances look suspicious, even if only a little, should be investigated (of course not all of them are sadly but still).


And when it comes to poisonings which can be difficult to investigate anyway due to the difficulties in finding what poison was used, and breaking the alibi of the killer (since that’s a good benefit of poisons. You don’t need to be in the same room at the time the poison takes effect) intentionality is key.


It’s up to investigators to work out what do the suspects gain from the poisonings?

Resulting in poisoners can go undetected for years, or forever, especially if their victims are members of populations who are expected to die. Like the sick and the elderly.


What Makes A Successful Poisoner?

Moreover, a successful poisoner is cunning, remorseless and often greedy or looking for a way out of a difficult situation. They also have to have the intelligence to study a poison and to plan ahead for its use and its consequences. As well as they need to know if how long the poison will take to affect the victim so they can plan their alibi according, and that’s all before knowing if the killer would prefer a slow or quick death, and how to hide symptoms.


Then staging plays a significant part as well.


For example, stagers try to find ways to defer investigations or mask symptoms. Since if you get investigators to believe that no foul play or poison was used then they aren’t going to investigate, meaning you don’t go to jail.


Some techniques for stagers include they could be flat out against an autopsy being performed and have the body cremated, they could write a suicide note or “confide” to a doctor that the victim was suicidal. Equally, they could clean up the crime scene, surround a search with context that obscures the value of what they find or wipe a computer search.


And what this idea of obscuring is about is the killer might have a ready explanation to explain away what the investigators find. For instance, a Minister once “discovered” his overdosed wife dead and he told the police that she was a sleepwalker and must have taken the pills by accident in her sleep.


Are Females Really More Likely To Poison People?

If you watch any crime programme there is always the popular idea that females are more likely to use poisons compared to other means of murder. But this is actually false since at least amongst the offenders caught for poisonings males outnumber females. However, this simply could reflect the biases in the criminal justice system that I talk about in Forensic Psychology, so more research should be done into this area.


In addition, medical professionals are overrepresented in this group of offenders (meaning more medical professionals are poisoners than other professionals). This is most probably down to their knowledge of as well as access to drugs and potential poisons. Since we constantly hear over and over how healthcare serial killers have accidentally given their victims

the “wrong” medications or administered an overdose.


Meaning it is critical we recognise these red flags in those who decide to poison others.


What Is The Criminal Psychology of Poisoning: Conclusion

To wrap up this podcast episode, I want to point out how Dr Farrel believed that murderous poisonings are underestimated. Due to given how easy it is for investigators and us to simply overlook the evidence, accept other explanations for a death and make investigative missteps and errors, he is probably right in actual fact.


Poisons can be all too easy to acquire and the motivations of people to use them are more often all-too-human and compelling to do so.


I really hope you enjoyed today’s episode.

If you want to learn more, please check out:



Forensic Psychology Collection. Available from all major eBook retailers and you can order the paperback and hardback copies from Amazon, your local bookstore and local library, if you request it.


Bettie Private Eye Mysteries Kickstarter includes a gripping private eye mystery about poisonings. Only available until the 28th July 2022.

If you’re reading after this, please check out The Federation Protects at all major booksellers.



Criminal Psychology Reference

Farrell, M. (2017). Criminology of Homicidal Poisoning. Springer.


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