An ESR scientist has told the High Court in Christchurch she used a low copy number DNA analysis technique for some tests in the trial of Liam James Reid because some of the samples were so small.
Forensic scientist Pauline Simon said she was "confident" in her results and interpretations after telling the murder and attempted murder trial of samples linking 36-year-old Reid to the crimes.
Reid is accused of the rape and attempted murder of a Dunedin student in November last year and also with the rape and murder of deaf woman Emma Agnew nine days earlier in Christchurch.
Dr Simon was challenged by defence counsel David Bunce about the use of the low copy number analysis, the Christchurch Court News website reported.
She said she had heard today that the technique was now being accepted by United States courts, and it had been used in Australia with the samples being sent to New Zealand for testing.
She said tests linked blood found on Reid's shoe to the victim of a sex attack in Dunedin, and there was also "very strong" scientific support for his DNA being in a sample taken from the victim's fingernail and from the rope tied around her neck.
The low copy number technique was used for the fingernail and rope samples.
She was asked if these two "partial profiles" could have come from different people, and if they could be from women.
"I can't exclude that possibility," she told Mr Bunce.
But during re-examination by crown prosecutor Marie Grills, Dr Simon said, "it is unlikely".
"I am confident in my results and interpretations I have made."
Dr Simon was in the witness box almost all day on the 12th day of the trial, in which Reid denies charges of raping and murdering Christchurch woman Emma Agnew, and raping, sexually violating, robbing, and attempting to murder a 21-year-old Dunedin student.
One police witness remains before crown closes its case tomorrow.
