Case investigation
Most cases that enter a forensic toxicologylabora tory start with the suspicion that a drug or poison is present. A fatality might be an accident, suicide or murder, but a toxicological examination must be carried out to assist the investigating officer to decide which of these it might be. Often the investigating officer will not know whether or not any offence has been committed until the results of the toxicological analyses are available, so that forming the correct questions for him or her to ask is vital if accurate and useful answers are to be given.
Thus, details of the circumstances that lead to the conclusion that a criminal action might have taken place must be supplied to the toxicologist so that the analyses can be planned. Figure 1 indicates the type of information that should be supplied along with the samples submitted for toxicological analysis. Not all this information will be available or relevant to all cases, but as much information as possible should be obtained and submitted as it will assist the toxicologist to use the most directly useful methods of analysis and to interpret the results in the context of the case at a later stage. If possible, a personal consultation with the investigating officer should be arranged, either in person or by telephone. A few minutes talking with the investigating officer can save many hours, or even days, of analysis time.
All those involved in a toxicological investigation need to consider the circumstances of a case. Although the discussion here is focused on forensic toxicology and the role of the forensic toxicologist, it is rarely the forensic toxicologist who encounters the body, be it living or dead, involved in an investigation. In the case of a reported poisoning or a suspicious death, the police and/or paramedics may be the first persons to attend the scene. They need to be aware of associated samples or circumstances that may be of importance in a toxicological investigation. For example, is there a fuel heater in the room which may give rise to carbon monoxide poisoning? Are there any medicines, drugs, drug paraphernalia or other suspicious materials near the body? Is there an odour which may implicate a certain poison (e.g. the smell of almonds pointing to cyanide poisoning)? Has the incident taken place in a place of occupation and, if so, what operations was the victim carrying out at the time of the incident? Samples need to be taken and packaged appropriately and passed to the toxicologist, with suitable storage through this process. Failure to manage this stage correctly can ruin any subsequent analyses. The pathologist carrying out a postmortem examination will be experienced in knowing which samples should be taken for toxicological analysis, but caution should again be exercised to ensure that samples are placed in appropriate containers and stored correctly before and during transportation to the forensic toxicology laboratory.
Where clinical treatment has preceded a forensic investigation, case notes and any samples taken during clinical treatment should be requested via the consultant physician responsible for the patient.
Figure 1 Information to be submitted with the exhibits in all cases in which there is suspicion of poisoning or doping.
