Lloyd Rayney's defence team has questioned the integrity of the forensic investigation and evidence about two liquidambar seed pods in Corryn Rayney's hair that prosecutors say show she was killed at home.
The suggestion came as a police forensics officer testified about a pathologist discovering the round, spiky seed pods as he felt in the hair behind Mrs Rayney's head during the post-mortem examination.
The State accuses Mr Rayney of wilfully murdering his wife at the couple's Como home on August 7, 2007, and prosecutors suggest soil particles inside one of the pods matched soil in the front yard.
Defence lawyers suggested yesterday that evidence about the pods' discovery during the examination was "flawed" and did not reflect the truth.
They also questioned why the pods were not treated like other forensic items in the case.
Sgt Siobhan O'Loughlin, who rejected the suggestions, had been testifying about a string of forensic items gathered during the post mortem on August 17, 2007 - just days after Mrs Rayney's clandestine bush grave was found at Kings Park.
Sgt O'Loughlin said she was not present for a preliminary examination of Mrs Rayney's head on August 16 but stood next to forensic pathologist Gerard Cadden the next day when two seed pods were pulled from Mrs Rayney's hair.
"Dr Cadden was examining the victim's head and during that process he has pulled something from the length of the hair . . . and placed it on the green sheet (under Mrs Rayney's body)," Sgt O'Loughlin said.
"He queried what it might be and I said, 'I think it could be important'."
Sgt O'Loughlin told the court Dr Cadden was standing at Mrs Rayney's head and feeling behind her head with his hands when he removed the pods "entwined" with Mrs Rayney's hair.
She said Mrs Rayney's body was lying face-up on the examination table on a green sheet and that the pods were placed on the same sheet and photographed after being removed from the hair.
No photos of the pods were taken "in situ" in Mrs Rayney's hair, the court was told.
Defence lawyer David Edwardson asked Sgt O'Loughlin why none were taken when in-situ images were taken for other exhibits during the post-mortem process, to which the sergeant replied it had not been possible.
"It (the location of the pods) was not visible to the external area," Sgt O'Loughlin said.
She said she was not able to see the pods before they were almost completely out of Mrs Rayney's hair.
Mr Edwardson also raised questions about why the pods did not have the usual exhibit number cards next to them when photographed.
He also questioned why the two photographs were not included in a hand-written list of coronial photographs taken during the examination.
The court has heard the photographs were later included in a typed list provided to the court. There was also evidence that data from the digital photographs of the pods showed they were taken half an hour after people involved in the examination returned to the secure government laboratory from a lunch break.
Mr Edwardson also quizzed Sgt O'Loughlin about images of Mrs Rayney's body lying face-down on the examination table that were understood to have been taken before the pods were discovered.
The court was told a running sheet Sgt O'Loughlin compiled as Mrs Rayney's body was exhumed on August 16 was missing and that a third seed pod was found in the body bag four months after the post mortem examination.
Sgt O'Loughlin rejected Mr Edwardson's suggestions that "in truth" the pods were not removed from Mrs Rayney's hair, that her recollection was "flawed" and that this was why no photographs of the pods in the hair existed.
She said no major crime squad officer had ever told her there could be an issue regarding the "integrity" of the pod exhibits.
Red brick particles found on Mrs Rayney's clothing are also alleged by the State to match particles found in soil at the Como home.