Some of the attacks by the lynch mob against Dr. Fowler clearly demonstrate a misunderstanding of the role of expert witnesses in these kinds of criminal cases. The thing to remember is that you have two sides in a case involving forensic pathology results:
- A prosecutor or plaintiff who has a theory of what has happened, usually supported by the results of a state-sponsored autopsy
- A defense who has *either* a counter theory *and/or* questions regarding the basis of the prosecutor’s theory.
The biggest problem, in my personal experience, is that courts and lawyers tend to think in categorical terms of absolute certainty. Either something is 100% certain (or close enough) or it is absolutely unknown. But that’s not how medicine usually works. Certainly there are trivial cases — an otherwise healthy person suffers a witnessed gunshot wound to the head. However, as I described in the last post, in many, if not most, cases. the determination of cause and manner of death is a function of weighing the value and importance of many pieces of information, some of which may be contradictory. The kind of inference that physicians do in diagnosis is complex, and not a simple matter of “deduction” or such(1)
The key here is that if you emphasize one set of data and de-emphasize another, you may come up with one conclusion, but if you emphasize and de-emphasize it differently, you may come up with a different one. The classic example is that of decompositional artifacts. Many things that happen to the body during early decomposition can mimic assault(2).
When an expert is hired by the defense, there are basically four outcomes that the expert can come to:
- I concur completely with the autopsy pathologist
- I concur with the autopsy pathologist, but the diagnosis is not absolutely certain
- The diagnosis by the autopsy pathologist is a possibility, but another option is more likely
- The diagnosis by the autopsy pathologist is wrong
Most of the time, a review will come up with option 1. Option 4 occurs rarely. Options 2 and 3, however, are very important for the defense. I recently consulted on a case where the diagnosis of strangulation was made because there were petechiae (small areas of bleeding) in the face. The problem is that petechiae are very often seen in cases of strangulation (there’s a high sensitivity), but there are a lot of other things that can cause them (there is a low specificity). In one study, over 90% of asphyxia cases showed petechiae, but they made up only 11% of the cases with petechiae. However, some folk will diagnose strangulation on the basis of petechiae alone. As a defense expert, it would be important for me to point out to the jury the problem low specificity if the autopsy pathologist opines that the decedent was strangled because of the presence of petechiae alone.
Looking for these kinds of things is a vital function. I have seen people railroaded because an autopsy report was accepted without question. I have seen postmortem artifacts mistaken for burns, and the defendant was wrongly convicted of murder aggravated by torture (which was reversed). I have seen people accused of murder based on time of death calculations that missed important modifiers.
To claim, as does the lynch mob attacking Dr. Fowler, that raising these possibilities is “unethical” denies basic defense to innocent people. In a viable legal system, if there are possible questions about a diagnosis, then those questions should be raised. If the diagnosis is certain, then the autopsy pathologist should be able to respond and deal with those issues. If there is room for uncertainty, then it should be acknowledged, and not covered over because it does not fit a political agenda, even an admirable social justice agenda.
- Oliver WR. Inference in Forensic Pathology. Academic Forensic Pathology. 2011;1(3):254-275. doi:10.23907/2011.037
- For a good example with respect to neck findings, see: Pollanen MS. Pitifalls and artifacts in the neck at autopsy. Acad Forensic Pathol, 6 (2016), pp. 45-62).
- Ikeda, T., Tani, N., Aoki, Y., Shida, A., Morioka, F., Oritani, S., & Ishikawa, T. (2018). Effects of postmortem positional changes on conjunctival petechiae. Forensic Science, Medicine and Pathology. doi:10.1007/s12024-018-0032-5