Forensic Toxicology

A question was asked in our Academic Forum Discussion in Forensic Toxicology Course at the University of Cambridge what caused Alex Death?

Today is the 3rd week into our course. I have already written out over 10 discussion tropics in the last two weeks. This is my 12th assignment

This is interesting question. Here's what I think as a student when I typed this on the 3rd Day of Chinese New Year 2020  (Tuesday, 28 January, 2020) sacrificing my Chinese New Year forever learning new disciplines.   

First of all, I have to admit this is the first time in my life I have been asked to solve a death mystery.


I am far from being a police officer, a crime investigator or a forensic scientist

But I shall try.

 Linda Watson is course Alex’s wife and works as a management consultant and lives with victim.

But she was away on business at the time of her husband’s death. Without her physical presence at the crime scene and at the time of Alex’s death, how could she be directly involved, unless she hired someone else to be the killer?

Clare Watson is Alex sister. Clare found Alex's body, and but claimed she has no alibi what actually happened when she visited the house on her own.

Furthermore, she lives a few streets away, but has the keys to her brother’s house. But it is not clear if Clare entered her brother’s house at the time of his death?

It may be yes, it may be no?  We don’t have the hard evidence. So we cannot work on assumption.  Clare works part-time at a local shop which has no relevance to the case.

The only human left to suspect is Stuart Thompson, Alex’s business partner as co-owner of Chemical Distribution Ltd. This is interesting as they deal with chemicals.

But what sort of chemicals it is not stated  – toxic chemicals like arsenic, cyanide, mercury, strychnine, ethylene glycol, pesticides like paraquat, or pharmaceuticals like cardiac drugs, example digoxin or what?

Even all drugs are just doll-up and refined names for chemicals, some highly toxic like cytotoxic agents used in cancer management, others are relatively “harmless” like aspirins and paracetamol, yet in high doses combined with alcohol they can kill.

So the first thing we need to ask is, what kind of chemicals were Alex and Stuart manufacturing? We have no clue.

Our question now is, was  the same chemicals or drugs they were manufacturing found on Alex’s internal body – blood, lymph, tissues, urine samples, stomach, intestines, liver (site of detoxification) or in the parenchyma of his kidneys (route of excretion)? This is a vital question.

However, Stuart claimed he was at work with his colleagues on Thursday 28th February. This can easily be confirmed with his colleagues. It is not a problem here.

Working with his colleagues at the time and date during Alex’s death again may not necessary mean Stuart has nothing to do with his death. 

He could have poisoned Alex’s food at the correct lethal dose when they went for dinner hours earlier or the previous night? Think of that possibility?

Drugs and poisons take time to be absorbed, distributed and excreted – pharmacodynamics and pharmacokinetics of drugs and poisons

Still, if the same chemicals or drugs were found in Alex’s body during autopsy we need to investigate Stuart further

Stuart lives 10 miles away from the victim’s house has no relevance to the case. He can live 100 miles away. That does not mean he cannot travel by car or other means of transport.

Now the other “chap” left that needs to be investigated was some poisonous insects such as harvester ants, and brown recluse spider or some poisonous snakes like vipers and cobras that bit Alex and ran away through the back door.  That is a very interesting proposition.  

Frankly this proposal gave me a silent smile when I read it.

But it is not stated the country where Alex was found dead. Some of these poisonous insects or snakes are not found in some countries. So we need to rationalize.

Even if Alex was bitten by a less poisonous animal that ran away that does not mean it was not the “poison’ that killed him.

In medicine we have to think of allergic reactions, and anaphylactic shock that follows. Even the slightest allergenic insults to someone who is sensitive, could result in fatal angioedema to the airways. He could have died of suffocation? Did we look into that?

Another possibility, could Alex have died of AMI (acute myocardial infraction – heart attack)?  

Only an autopsy can demonstrate the cause of the death, not necessary some poisonous chemicals, natural or synthetic or overdose of some lethal drugs, or blame it on his business partner or family members.

We need to send Alex body for post mortem for a definitive cause(s).  We cannot assume anything before a post mortem and confined by toxicological analysis. Initially we can only look at suspicious clues. They are not even evidence(s).  

If I were to be asked to investigate in such circumstances, firstly I would take samples of blood, saliva, biological fluids, urine, tissues, especially from the liver and kidneys for analysis.

ELISA is very useful in such cases, easy to use, rapid with high sensitivity and specificity if it involves a biological bite from some animals that triggers off an antigen-antibody reaction unlike chemicals whose toxicodynamics may be through other biochemical pathways.

If no insect or animal bite were found that may elicit a serological / immunological response, then we need to interview all the 3 suspects again, especially Stuart, Alex’s business partner.

This is just my amateurish “detective work”

I admit I may be off tangent. After all I am just a student in this forensic toxicology course.

In that case please forgive me else I would not be taking this course out of curiosity

Thank you dear course mates at the University of Cambridge for listening

lim ju boo

Malaysia