Van Breda de­fence ques­tions the DNA

Weekend Argus (Saturday Edition) - - FRONT PAGE - THEOLIN TEMBO

DNA SAM­PLES found in Henri van Breda’s bath­room did not con­clu­sively prove that there had been three peo­ple there.

This emerged on day 31 of the Van Breda trial in which Henri van Breda is ac­cused of mur­der­ing his par­ents, Teresa and Martin, and his brother, Rudi, and at­tempt­ing to mur­der his sis­ter Marli.

De­fence ad­vo­cate Matthys Com­brink con­tin­ued to lock horns with the chief foren­sic an­a­lyst at the po­lice’s foren­sic lab­o­ra­tory, Lieu­tenant-Colonel Shar­lene Otto, as she was in­tensely ques­tioned about the DNA ev­i­dence and Stan­dard Op­er­at­ing Pro­ce­dure (SOPs) yes­ter­day.

Otto took the wit­ness stand in the West­ern Cape High Court on Mon­day to give ev­i­dence about the DNA pro­files of the Van Breda fam­ily, and the pro­ce­dures in­volved when pro­cess­ing DNA ev­i­dence. Yes­ter­day, Com­brink con­tin­ued in­ter­ro­gat­ing the ex­pert wit­ness about the in­put of DNA to be an­a­lysed. Otto had tes­ti­fied that they needed 0.005 nanograms per mi­crolitre af­ter qual­i­fi­ca­tion to be able to cre­ate a DNA pro­file.

Any­thing less and the ma­chine they used would not be able to cre­ate a suf­fi­cient pro­file for the an­a­lyst.

“It’s dan­ger­ous work­ing with too lit­tle DNA and dan­ger­ous when work­ing with too much, which is why there is a set amount,” she ex­plained ear­lier this week.

She added yes­ter­day that when look­ing at DNA, an­a­lysts only look at white blood cells, and that in foren­sics it’s not about quan­tity but qual­ity.

“The av­er­age foren­sic sam­ple is not your op­ti­mal sam- ple,” Otto said.

Com­brink in­ter­ro­gated the DNA ev­i­dence that was found in Henri’s bath­room shower. Otto had pre­vi­ously said that she couldn’t fully state that this was blood, but it was DNA.

On Mon­day, she in­di­cated the three DNA pro­files found in the cor­ner of the shower be­longed to Rudi, Henri and their mother, Teresa. How­ever, dur­ing cross-ex­am­i­na­tion Otto re­vealed that in in­stances of a mixed re­sult, since Rudi and Henri share 50% of their DNA with their mother, she couldn’t un­equiv­o­cally state that the DNA be­longed to only two or three peo­ple. Just be­cause three pro­files matched the sam­ple that was tested, it didn’t mean that the three peo­ple were nec­es­sar­ily there.

Ear­lier in the week, State lawyer Su­san Gal­loway had tried to as­cer­tain if some­one could en­ter an en­vi­ron­ment, and not leave ev­i­dence, to which de­fence ad­vo­cate Pi­eter Botha ob­jected, stat­ing this was invit­ing the wit­ness to spec­u­late.

Gal­loway then al­lowed Otto to ex­plain the “Lo­card prin­ci­ple” which states that “ev­ery touch leaves a trace”.

Dur­ing cross-ex­am­i­na­tion, Otto had said that if a per­pe­tra­tor was wear­ing pro­tec­tive gear, it was pos­si­ble for them to not leave a trace.

“If a per­son is wear­ing a bal­a­clava and gloves, with normal clothes, I wouldn’t ex­pect them to leave DNA,” said Otto. She ex­plained this was be­cause the face and hands of­ten shed a lot of DNA nat­u­rally.

Otto said in such in­stances the en­vi­ron­ment would leave a trace on the per­son wear­ing the pro­tec­tive gear.

The trial con­tin­ues on Mon­day.

PICTURE: DAVID RITCHIE

Chief foren­sic an­a­lyst Lieu­tenant-Colonel Shar­lene Otto un­der cross-ex­am­i­na­tion in the Van Breda trial in the West­ern Cape High Court.

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