When expert witnesses give conflicting evidence

Friday April 01 2016
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On Monday, July 27, 2015, a 19-year-old young man was arrested by security personnel on patrol in one of the towns in northern Uganda. The young man was taken to court on Wednesday, July 29, 2015 and was then remanded to prison. However, the following morning, on July 30, 2015, the young man was reported to have died under unclear circumstances. It is mandatory that a medico-legal postmortem is performed on anybody who dies while in custody. It is for this reason that the body of the young man was transported to the mortuary and a doctor was called to carry out a postmortem. The doctor found that the liver of the deceased was grossly enlarged and concluded that the young man had died of hepatitis, a viral infection of the liver.

The outcome of the postmortem raised a number of questions, not least of all the competence and integrity of the doctor who performed the postmortem. The young man was not known to have been suffering from hepatitis and it is extremely rare for hepatitis to cause death within such a short time. A human rights advocate went to court to contest the cause of death.

New postmortem
The Chief Magistrate’s court ordered for a repeat postmortem, pending burial of the body. A pathologist was called upon to repeat the postmortem which was done on Monday, August 10, 2015. The pathologist did not find any features of hepatitis in the liver. Instead, the pathologist found that, contrary to what the first doctor had stated, the young man had died as a result of physical injury he had suffered. Court accepted the findings of the pathologist.

Why were the results of the two postmortems so diametrically different? What could have gone horribly wrong as to produce such divergent results? There are indeed a number of reasons why expert witnesses may give or produce conflicting evidence.

The first doctor to carry out the postmortem, although a specialised doctor in another branch of medicine, was not a pathologist. He therefore lacked the necessary experience and knowledge of investigating this particular death. This doctor simply had inadequate training to investigate such a death. Deaths as a result of torture require special investigative techniques.

The doctor should have consulted his colleagues, especially those with training in forensic pathology, the branch of medicine that deals exclusively with death investigations. A prudent doctor should know when to consult and when to refer a case. This particular case was complex and not one encountered commonly.


Death investigations must be carried out carefully and diligently. It is vital for a doctor investigating a death to find out about the circumstances of the death. This is not to bias the doctor, but rather guide him or her. In this particular case, the pathologist was informed that the deceased had been beaten and tied up in a stressful posture by fellow inmates the night he died.

New evidence
The pathologist found injuries on the body of the deceased consistent with being tied up. Apparently the first doctor who carried out the postmortem was not told this or he simply ignored this fact or he was deliberately misled by the information provided to him. He therefore failed to correlate the scientific findings with the circumstances of the case.

Samples of tissues were taken from the body of the deceased and these were examined under the microscope. This examination under the microscope confirmed that the young man had died as a result of the trauma he suffered. The first doctor did not carry out this vital examination. It is important to follow up standard protocol, guidelines and procedure while carrying out death investigations.

Where these are not in place, experts may come up with all manner of reports, some of which may be erroneous. True, the liver of the deceased was enlarged, but it was due to a very different cause not even remotely related to hepatitis. And the enlarged liver was not responsible for the young man’s death.

And health workers should not be under pressure of any kind to release postmortem results and they should not release these results in a hurry. These results should only be released after thorough investigations.

In well established forensic units, the findings at postmortems are always discussed by a team. This allows for peer review, which is a quality control measure. It also allows for colleagues to consult among themselves and protects the doctors when their integrity or motives are questioned.