The cross-examination of Lt. Coln. Otto continued this morning, and although it started along similar lines as the last two days, it started getting more interesting this afternoon, with the Defence raising some serious doubts about the DNA evidence.
In Lt. Coln. Otto’s report, she stated that the DNA of Henri, Rudi and Teresa was found in the blood sample taken from the shower floor. She said that she assumed this to be DNA from blood, which is less likely to be washed away in a shower, due to the resilience of blood over skin cell DNA.
Under cross-examination, Otto conceded that it is possible; Henri and Rudi’s DNA contains their mother’s DNA, that the sample only contained the DNA profile of Henri and Rudi. In other words – Teresa and Martin’s profile may have only been identified because their sons’ DNA contain their DNA.
Otto explained why. She told the court, under cross-examination, that in certain instances DNA results recognize a ‘mixed profile’ in a sample such as a blood sample, which can include DNA from a parent. That doesn’t necessarily mean that the parents’ blood is in the sample, rather it identifies that a parents’ DNA could be in the sample, or it could be detected through their child’s.
The Defence used the possibility of the ‘mixed profile’ result, illustrated on the DNA found in the sample of taken from the shower floor, to argue this could be possible in this sample. In fact, this could be the case for each and every mixed result contained in Lt. Coln. Otto’s report where a child’s DNA was recognized. There is a possibility of a parent’s DNA also being recognized even if it did not come from the parent.
Now, the court will need to consider all the mixture results in this light. Where we initially thought that Rudi, Martin, Teresa and Henri’s DNA was found on Henri’s shorts we now know that due to Rudi and Henri’s DNA containing their parents’ DNA, the samples have this mixed profile, and it may only have been Rudi and Henri’s blood or skin cells not Martin’s and Teresa’s too.
This is obviously a huge concession for the Defence, as it is easier to argue Rudi’s DNA away – Rudi and Henri shared a bedroom and bathroom and possibly even clothes – than arguing why three of the deceased’s family members’ DNA was on the shorts Henri wore that night.
So the fact that the victims and accused are family makes it difficult to draw conclusions from what is ordinarily quite objective DNA evidence.
One other important aspect which the Defence uncovered was the possibility of foreign DNA being present in samples.
Otto said, in her evidence in chief, that no foreign DNA was recognized in any of the samples which she had analysed. Under cross, the DNA profiles were scrutinized and the Defence showed the witness three instances where a DNA allele* was present which were not allele that were identified with any of the family members.
Otto explained this to the court as well. Her view on this is that there is a peak which means that the laboratory system has identified a small possibility of DNA but the presence is too low, or there has been an error and the system will not label it as an actual allele. If the system does not label it as an allele, an analyst would not be allowed to interpret that DNA although it may possibly be an allele. This evidence was all very technical, and both sides will have to deal with this in argument, but what will become important from today’s evidence is that when considering whether the statement that no foreign DNA was found on any of the 216 samples, Jugde Desai and his assessor will have to consider whether that is, in fact, acceptable beyond reasonable doubt.
*What is an allele? *A gene is a stretch of DNA or RNA that determines a certain trait. Genes mutate and can take two or more alternative forms; an allele is one of these forms of a gene. For example, the gene for eye color has several variations (alleles) such as an allele for blue eye color or an allele for brown eyes.
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Photography K-leigh Siebritz / HM Images