A likely DNA match for a man accused of murdering a pregnant McDonald’s worker was found on a piece of her clothing, a Queensland court has heard.
Andrew Michael Burke pleaded not guilty to the rape and murder of Joan Ryther on May 21, 2013, as well as killing her unborn child, on the first day of his trial last week.
A Brisbane Supreme Court jury on Tuesday heard evidence from forensic DNA analyst Jacqueline Wilson, who said an area of Mrs Ryther’s green jumper was found to be “100 billion times” more likely to also contain DNA contributed by Mr Burke than not, along with one other person.
The court heard one of his black shoes was also found to have a similar statistical likelihood of carrying her DNA, while a hand bandage obtained by police also suggested a match.
Other samples also showed varying likelihoods for a number of people from the more than 20 reference profiles provided, with some returning results suggesting it was more likely Mr Burke had not contributed DNA, it was heard.
Under cross-examination, Ms Wilson agreed with lawyer Michael Bosscher’s suggestion the risk of contamination was present from the moment DNA was transferred from one person or object to another and there were a number of factors that could affect the integrity of a sample.
She said a coding error had been detected in a software program, used as part of the DNA analysis process, but it had since been amended and the affected results were revised.
It came after crown prosecutor Glen Cash told the jury during his opening that Mrs Ryther, who was eight weeks pregnant, was “viciously assaulted” as she walked to an evening shift at the Logan Central McDonald’s where she worked.
The trial continues.