Dna Case Study

DNA was collected from a small blood stain on Ms Lees’s T shirt which was located on the left shoulder and examined. The result produced a profile which was identical to the DNA profile of Bradley Murdoch. The forensic scientist stated that this DNA profile is at least 640 million times more likely if it had come from the accused than it had come from a non-related person selected at random. DNA evidence had a huge impact on the case because it linked the accused’s presence to the event at Barrow Creek.

In addition, Ms Carmen Eckhoff, the investigating forensic scientist had also found a small portion of DNA on the gear sticks and the steering wheels from the couple’s Kombi van. She reported obtaining “ an extremely weak and partial DNA” on the gear stick

knob and the relative frequency is “approximately 1 in 678 individuals in the Northern Territory and includes the accused. In October 2004, Ms Eckhoff flew to UK and handed the DNA sample found on the swab to Dr Whitaker of the Forensic Science Service Laboratory at Wetherby. Dr Whitaker and his team developed a technique called “Low Copy Number” which allowed examining of a very small DNA portion.

Sample from the steering wheel showed a mix DNA sample and Dr Whitaker was unable to exclude the Peter Falconio, Ms Lees or the accused as being one of the main contributors. However, a mix profile found on the gear stick knob would be best explained if there were two sources of DNA. In his assessment of DNA bands, only small amount came from the deceased and the rest were all represented in the profile of the accused. Objection was raised from the defence concerning the evidence from the steering wheels and gear stick knob were contaminated by Dr Whitaker while he was carrying out his testing and was not available for them to conduct an independent test on behalf of the accused. Nevertheless, objection was declined because Dr Whitaker pointed out his methodology didn’t alter or destroy the DNA in anyway. Another issue was brought up regards to the validity and reliability of “Low Copy Number” technique. Senior counsel who appealed for the accused, Dr Katrin Both referred to the above technique as “very dangerous” and “pushing science to its limit” and identified several different areas which concerned her. Plus the fact

that Wetherby was the only laboratory in the world that used the technique to test DNA sample raised questions on its reliability and validity. Judge later accepted the evidence of Dr Whitaker because his methodology and research had been accepted by other scientists in the scientific community and also reviewed by an independent organisation referred to as UK Accreditation Service. This further enhanced the connection of the accused’s presence to the assault of Joanne Lees and disappearance of Peter Falconio.