DNA from 3 men on underwear, court told

Traces of DNA from two men were discovered on murdered An An Liu's underwear, and DNA from her husband, murder accused Nai Yin Xue.

The red underwear was found wrapped in a pair of pyjamas in the boot of Xue's car, alongside Ms Liu's naked body.

In a further revelation in the High Court at Auckland yesterday, DNA probably belonging to Xue was found on the tie used to strangle Ms Liu to death but so was a smaller DNA sample from another man.

ESR forensic scientist Dr Sally Harbison, giving evidence at Xue's murder trial, said DNA from the waistband of the underwear was consistent with the murdered woman as well as a mixed DNA profile whose major component could have come from Xue.

But Dr Harbison said "minor trace components" from two other men were also found.

The Crown alleges Xue strangled his wife on September 11, 2007, and then fled to the United States, abandoning his 3-year-old daughter in Melbourne on the way.

Dr Harbison told the court she obtained a mixed DNA profile from male DNA present on the waistband of the underwear, but there was more than one contributor.

Xue could not be excluded from contributing the major component, she said.

The doctor found that most of the DNA on the tie most likely originated from Xue or a paternal relative but there was also trace amounts of additional male DNA from another man that could not be Xue.

His flatmate has also been ruled out as the source.

Dr Harbison said the amount of female DNA on the tie was 100 times the amount from Xue, which would be "a very small amount of cells not visible to the naked eye".

She said it was quite common for DNA, for example, skin cells and saliva, to be transferred, especially in outer garments where it wasn't uncommon to find "DNA from other sources".

Transfers could be by coughing, sneezing or touching.

She told prosecutor Aaron Perkins it was possible DNA could be transferred from garment to garment.

Under cross-examination by defence lawyer Jesse Soondram, Dr Harbison said it was not surprising Xue's DNA would be found on a tie that was assumed to belong to him and in garments that could have been washed with Ms Liu's.

Mr Soondram: "Assuming the underpants were regularly washed, is it surprising to find two male DNA contributors?"

Dr Harbison said it was possible for DNA to survive a wash, but it was surprising to find "so many contributors" in a piece of underwear.

Asked to comment on the possibility the male DNA detected on the underpants and tie were from the same person, the doctor said she couldn't be certain but thought it likely.

However, asked if she could exclude the possibility that whoever killed Ms Liu was the same person who left the sample, she said she couldn't comment without reference samples.

The Crown is expected to conclude its evidence today.