A doctor who examined Laniet Bain the year before she was killed has told a High Court jury the woman was anxious about going to spend four days with her father.
Marjolein Copeland was giving evidence for the defence in the retrial of David Bain in Christchurch on Friday.
The Crown accuses David Bain, 37, of killing his parents Robin and Margaret and siblings Arawa, Laniet and Stephen at the family's house in Dunedin on 20 June 1994.
The defence says Robin Bain killed those present in the house before shooting himself.
Dr Copeland told the court that she examined Laniet Bain in November 1993 when she was working as a prostitute.
She said Laniet Bain took a call on her cellphone during the consultation and told her she was going to spend four days with her father at Taieri Mouth.
Dr Copeland told Laniet Bain that she probably had a sexually transmitted disease and advised her to abstain from sex for four days.
The doctor said Laniet Bain then became anxious and said that would not be easy.
The defence maintains Robin Bain was having an incestuous relationship with Laniet Bain and killed his family and himself because she was about to reveal the abuse.
Earlier, forensic scientist John Manlove said it would be inconceivable for Robin Bain to have been sitting when he was shot.
The Crown says David Bain shot his father while he was praying, which is more consistent with a sitting position. The defence maintains Robin Bain was standing up and shot himself.
On Thursday, Dr Manlove agreed with a Crown proposition that the pattern of bloodstains on Robin Bain's trackpants could be explained if he was sitting with his knees bent.
But in re-examination on Friday morning, Dr Manlove said looking at the scene as a whole, it was inconceivable that Robin Bain could have been sitting because blood spatters on the curtain were at the wrong height.
A British fingerprint specialist told the court on Friday that David Bain's fingerprints on the rifle used to kill his family had not been applied with pressure.
Police fingerprint expert Kim Jones earlier gave evidence that David Bain's fingerprints had been applied to the .22 rifle with bloodied fingers and with considerable pressure.
But defence witness Carl Lloyd testified on Friday that the prints showed no pressure.
Mr Lloyd said he believed the prints were not put there in blood, but were latent prints that had been chemically enhanced with super glue before they were photographed by police.