Criminal Poisoning: Investigational Guide for Law Enforcement, Toxicologists, Forensic Scientists, and Attorneys (16 page)

When considering a product tampering, investigators must ask themselves these questions: Could tampering of the product have occurred during the manufacturing process, at the hands of an employee, or as a form of industrial sabotage? Could it have occurred during distribution of the product and then the product been returned to the shelf looking untouched (remember the “poisoner camouflage,” in which the offender has a specific victim in mind and tries to make the crime look like a random death). Could it have occurred after the point of purchase (which is when an individual seeking a financial settlement from the manufacturer makes a false report)?

5.6.2. Analytical Toxicology

We now come to the part of the investigation in which a specialized form of chemical qualitative and quantitative analysis takes place. This is usually done in a forensic toxicology laboratory. The criminal investigator needs to remember that these analytical tests do not routinely test for all chemical substances. Forensic toxicology laboratories normally have a set of specialized toxicology screens that they utilize. These general tests usually are drug screens, which look for commonly abused substances; heavy-metal screens, which look for substances such as arsenic, antimony, thallium, or lead; and volatile substance screens, which look for solvents such as chloroform or ether. There may also be general analytical screens, which detect cyanide, volatiles, strychnine, heavy metals, and drugs.

Remember that when a result comes back negative, it means only that none of the substances tested for were present in detectable quantities, not that the specimen was free of all chemical substances. It would be nice if someday, like
Star Trek’
s Dr. McCoy, we could pass a medical “Tricorder”

over the body in question and thereby scan for more than a million different chemical entities. Unfortunately, such technology is too far in the future to be of help to us at present.

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However, it is quite possible for the criminal investigator and pathologist to be of great assistance to the team running the toxicological analyses, by providing an indication of what substances are suspected. This help comes from the death scene investigation and any abnormalities found on autopsy.

Remember, one cannot find what one is not looking for.

Typically the analytical toxicology laboratory will use one or more of the following methods in its qualitative and quantitative analyses: •
Color tests
: Cheap, easy, and quick.

•
Immunoassays (radioimmunoassay [RIA]):
Utilizing antibody reactions.

•
Thin-layer chromatography, or TLC
: This method is based on the separation of substances based on their movement through a matrix by a defined solvent system. The unknowns are then compared with a known standard based on what is known as their Rf values.

•
Gas chromatography, or GC.

•
Ultraviolet spectroscopy, or UV.

•
Mass spectrometry, or MS
: A procedure akin to “fingerprinting” molecules.

•
Gas chromatography/mass spectrometry, or GC/MS:
Currently the most powerful method for confirmation of substance identification.

It is also important to remember that the analytical work can only indicate the presence and possible quantity of a poisonous material, not the reason for the exposure. It is up to the death investigator to determine the reason for the exposure. One observation that might be helpful is that there can be differences in the quantitative amount of the lethal material. In a homicide, usually just the right amount for a lethal dose is given, whereas in a suicide, usually a massive amount is taken.

To carry out a proper toxicological analysis, the analyst must have the proper specimens. In gathering specimens for testing, one must be absolutely certain that all specimen containers are clean and not contaminated, and that the proper chain of evidence has been maintained. Ideally, the specimens and amounts needed for analyses are as follows:

• Urine = all available.

• Gastric contents = all available.

• Blood = 25 mL (heart), 10 mL (peripheral).

• Brain = 100 g.

• Liver = 100 g (to look for metabolites).

• Kidney = 50 g.

• Bile = all available.

• Vitreous humor (from the eye) = all available. (This specimen’s levels usually lag behind the blood levels by ~1 to 2 h.)

• Hair and nails = hair (include roots), nail (one full specimen). (Hair usually grows ~0.5 in. [1.25 cm] per month and can be used for a segmental analysis.)

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Figure 5-2

Fig. 5-2
summarizes these points.

The results of the analyses must be interpreted with care. The following questions must always be answered: • Was there the possibility of a laboratory error owing to contamination? Were acid-washed containers used?

• Is the laboratory capable? Is it certified?

• Is the result reproducible? Second opinions should be obtained by utilizing a different laboratory using the same analytical procedures.

• If the level is indicated as being high, who made that determination, and by what standard reference? The term “high” can be subject to interpretation by the individual conducting the analysis.

5.6.3. Analysis of Cremated Remains

Although it would seem, at first glance, that the ashes of a deceased person could be analyzed for toxic substances, this does present some very definite analytical and legal problems. For example, many chemical substances will be burned off at the high temperatures required for cremation, which would yield a false negative result. In addition, legally, one cannot prove that a sample is pure, because it could be contaminated with other cremated remains; therefore, the chain of evidence is broken. One would also not be able to prove that the 78

Criminal Poisoning

poison was in systemic circulation and therefore caused the death. Furthermore, one would not be able to prove in what organ the poison originated, and, therefore, there would be no basis for comparison (e.g., milligrams of arsenic per gram of liver). Although the analysis of cremated remains was used in the poisoning conviction of Graham Young in the United Kingdom in 1972, it seems that this type of evidence has too many pitfalls to warrant its use.

5.6.4. When Should the Criminal

Investigator’s Suspicion Be Aroused?

The astute criminal investigator might begin to wonder if it is ever possible to detect murder by poison, and if there is anything that might serve to warn an investigator of the possibility. Some things that might come up in an investigation that should send up a red flag are as follows: • The death occurred in a normally healthy individual. Certainly a person can die without warning, but when this type of death occurs, a deeper look into the cause is called for, including an autopsy.

• An individual interfered with the victim receiving proper medical attention. This may lead one to wonder if that person does not want educated eyes and minds delving into the possible cause of the condition in question.

• There is no sign of violence to the body. This is always an indication that the death could have been the result of a poisoning misadventure.

• The affliction appeared as a natural disease yet failed to respond to normal treatment methods.

• An illness reoccurred in cycles; that is, the victim became ill at home, went to a medical facility and seemed to recover, then went home and became ill again, and so on. This would indicate that there is something in the home environment that is proving unhealthy for the individual. Could it be the chronic administration of heavy metals (e.g., arsenic) in the person’s meals? There certainly have been recorded criminal cases in which this has happened, and the poisoner is often not caught in the initial stages of the homicide attempt.

• There are common mysterious symptoms in a common group of people. This could indicate that there has been a mass tampering, or that the supposed specific target was a off the mark of the poisoner.

• There is an individual who is anxious to dispose of food, drink, or medicine of which the victim partook. In this case, it is clear that the person is attempting to foil the investigation by destroying critical evidence.

• An individual prevented friends or relations from being sent for during the victim’s illness. The criminal investigator should question what that person did not want others to witness.

• There is an insistence on no autopsy. The criminal investigator should clearly state that one will take place. Once again, the desire not to have educated minds look at the problem comes to the forefront.

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Figure 5-2

• There is an insistence on a rapid cremation. This could be construed as an attempt to burn the primary evidence of the crime and foil the investigation. The criminal investigator should clearly state that an investigation must take place before cremation can proceed.

• While grieving over the loss of a close family member or friend, a certain individual does not freely begin to offer an explanation for the cause of death. Neither will the person attempt to guide the investigation in any way. If the person does, it could very well be an attempt to divert investigators’ attention from his or her crime, and investigators must be aware of this.

• An individual shows a familiarity with poisons and possesses literature about poisons. In this case, not just a red flag should go up, but a whole sky full of mental fireworks.

Fig. 5-3
summarizes these important points.

5.7. HOW DID THE POISON GET IN THE PATIENT?

Once it has been determined by autopsy that poison was present in the victim, the question arises: How did the poisoning occur?

It is possible that the cause was accidental. The poison could be present from a natural source, such as heavy-metal contamination of groundwater in the environment, or contamination of the body by leaching of heavy metals 80

Criminal Poisoning

prior to exhumation. Another natural source is food or drink, such as seafood, which causes temporary elevation of arsenic levels after consumption. Elevated levels of poison such as lead can result from occupational exposures, such as in jobs at shooting ranges, electroplating facilities, or smelters. There could also be a possible metabolic cause for the presence of the poison in the deceased, such as the elevated copper levels one sees with a condition known as Wilson’s disease. Poisoning could be the result of filling a prescription with the wrong medication or providing incorrect instructions for a drug’s use, or it could be the result of contamination in the home environment, such as carbon monoxide.

The poison could have been self-administered, as in the case of the accidental misuse of a product, the unforeseen result of substance abuse, or the intent of the victim to commit suicide.

The poison might have been administered by another person, perhaps from product tampering or with homicidal intent. For example, an individual is found with an extremely high level of insulin (hyperinsulinemia). Did it come from outside the body, or was it naturally produced internally? With this type of compound, it is easy to answer this question. Normally, when the beta-cells of the pancreas produce insulin, they produce one molecule of insulin plus one molecule of what is called C-peptide in a 1:1 ratio. Thus, if the victim’s insulin level is high and the C-peptide level is also high, then the insulin source was from inside the body (e.g., from an insulinoma [insulin-producing tumor]). However, if the insulin level is high but the C-peptide level is not also proportionally high, then the source of insulin was from outside the body (injected in an accidental, suicidal, or homicidal event).

In all, the poisoning crime scene is one surrounded by mystery and invisible clues. But when a criminal investigator begins to focus on the possibilities, the mysterious fog begins to clear a little, and the face of the poisoner becomes more visible.

Our ability to detect poisons has greatly improved over the last 100 years, but our ability to suspect poisoning in the first place has not improved, and may have actually gotten worse.