The Importance Of Toxicology In Legal Cases

Chances are you have heard of the case of Erin Patterson, who last month pleaded not guilty to charges of the murder and attempted murder of her relatives after she served them a meal of beef Wellington allegedly laced with death cap mushrooms. The Australian court drama has gripped the international media, not only due to the extraordinary circumstances of the case but also because of the Forensic Toxicology Expert Witness reports on the terrible suffering the victims would have gone through before they died.  

Forensic toxicology has also been in the spotlight in many high-profile UK cases, including the Salsbury poisonings of Sergei Skripal and his daughter, Yulia. This event was to result in the death of a British national, Dawn Sturgess. Toxicology reports confirmed that the victims had been exposed to the deadly nerve agent Novichok.

Forensic Toxicology Expert Witnesses advise the Court on one of the most complex issues legal professionals can face and help piece together what happened in both criminal and civil cases.

What is forensic toxicology?

hand holding toxicology drug test

Forensic toxicology is the analysis of blood samples for the presence of a substance or toxins, including drugs and poisons. A toxicology report provides information on the type of toxin or substance present in a person’s body and whether the level could cause damage. These results can be used to make inferences when determining a substance’s possible impact on a person’s death, illness, or mental or physical impairment. 

A forensic toxicologist will know the likely effect of a particular substance on a human being. In BK-S v Hampshire County Council & Ors [2015] EWCA Civ 442, 2015 WL 2023482, a child, Z, had been discovered to have the drug Olanzapine in his body on three occasions. Olanzapine is an antipsychotic drug used for the treatment of schizophrenia and bipolar disorder and is only available on prescription. Z had not been prescribed Olanzapine and large doses can be fatal in children.

Z had been admitted to hospital on three occasions: the first was thought to be for gastro-enteritis, the second and third were for an undiagnosed illness with an overlay of altered consciousness. On the third occasion, bloods were taken which showed a concentration of Olanzapine in Z’s blood of 257 micrograms per litre (ug/L). Nine days later, another test found 43 ug/L. As a consequence, all of the children were taken into care. The potential perpetrators were the mother, the father, and the paternal grandmother. There was no evidence of accidental ingestion, and all denied responsibility or having any access to the drug.

A Forensic Toxicologist Expert Witness was instructed to analyse Z’s blood test results. He provided evidence to the Court that:

  1. ingestion of the drug would take longer if it were in solid rather than solution form,
  2. peak symptoms would occur two to five hours after administration,
  3. peak efficacy and peak symptomology would coincide with the highest level of concentration of the drug in the body, and 
  4. the symptoms that would be observed in a baby or young child who had ingested the drug would be tiredness, lethargy, and agitation.

Although the forensic toxicologist’s ability to draw conclusions was limited due to him only having partial knowledge of the test results, the Court of Appeal stated that he could give an opinion on the suspected perpetrators’ “window of opportunity”.

Referring to academic literature, the toxicologist stated that “the half-life of the drug in children would be quite a bit shorter than in adults”, being around 12-24 hours. To assist the Court, he prepared a schedule demonstrating a predicted administration time and date, a matter of particular importance to determine who was with Z when they received the drug.

How easy is it for a Forensic Toxicologist to establish causation in Personal Injury cases?

Establishing causation in cases concerning a claim for occupational disease can be challenging. As one expert wrote, long latency periods between exposure to a substance and the onset of symptoms, as well as lifestyle factors such as smoking, alcohol consumption, and other use of chemicals (for DIY or personal grooming), can make it difficult to say for sure whether historic exposure to a particular substance, for example, Polycyclic Aromatic Hydrocarbons (PAHs) or Polyfluoroalkyl substances (PFAS), both known carcinogens that those doing certain occupations such as firefighting are regularly exposed to, actually caused the disease suffered by the Claimant. Past medical records often have to be analysed alongside toxicology reports to establish causation. 

Concluding comments

Given the complexity and challenges around making inferences from toxicology reports, especially concerning the issue of causation and remoteness of damage, it is essential to instruct a Forensic Toxicology Expert Witness who has extensive experience and who can explain complex scientific information in a way that is understandable to the Court and jury.

How can Expert Court Reports Ltd help?

A forensic toxicology expert witness should come with years of clinical experience as well as specific competencies to act as an expert witness. Our forensic toxicology expert, Dr Salah Breidi, has many years of clinical practice. He has acted as an expert witness at the United Kingdom High Court, Family Courts, County Court, Magistrate Courts, Tribunals etc. Dr Breidi has investigated and reported thousands of toxicology cases of forensic toxicology investigations.

Expert Court Reports provides expert witnesses and medicolegal court reports for solicitors, barristers and other agencies including the police, probation services, prisons, and third-sector organisations as well as private clients. To discuss any issues raised in this article, please call us on 01865 587865, email, or request a call by completing our online form.