IMO Almost all of the experts have given testimony way beyond the scope of their expertise. Part of that is the attorneys asking them their opinions about things that are not part of the expertise - both Roux and Nel have done it while cross examining witnesses, and they have both gotten experts to make observations and give opinions that are really the province of fact witnesses or lay witnesses. It is baffling and also intriguing to me.
What many of the "guilty" crowd are seeing in Dixon, I was seeing in Vermuelen - astounded that an "expert" in materials (i.e., a geologist and chemist) would be doing a demonstration of body position in such a non-scientific and haphazard way and giving tool mark opinions without being certified in tool mark examination. There was nothing exact about his process at all. Same with Van Staden and the whole business with taking crime scene photos while others were mucking about with the evidence.
Even Mangena trotted into territory that was beyond his field when he started giving opinions about pathology.
This must be something that is common in South Africa -- and obviously it is great fodder for the opposing counsel on cross examination.
But I read a legal article the other day that might shed some light on this phenomenon. The SA judicial process was described as part adversarial and part inquiry ...meaning that information is presented to inform the judge as much as possible. I think this is why there are not so many rules of evidence and pre-trial challenges to experts and such; no hearsay objections, etc. Since it's a bench trial and no jury, the judge can sift through the evidence and give it the proper weight without being prejudiced.
With that in mind, it makes more sense that a witness might give testimony or do demonstrations that are not precise or exactly replicative of the night in question. The sound test wasn't meant to demonstrate that those sounds were exactly what witnesses heard on that night - the purpose was simply to inform the judge that a cricket bat hitting the door is very loud and could be interpreted as a gunshot. That's it. And for that purpose, the defense accomplished its goal through Dixon.
The judge has now at least heard a demonstration that provided enough information for her to put the cricket bat sounds in context with the witness testimony.
