A former detective who was part of the initial Bain family murder inquiry has admitted he sprayed the words 'hang Bain' on his own house.

Milton Weir is still being cross examined by lawyer Michael Reed at David Bain's murder retrial at the High Court in Christchurch.

He has been asked why he painted the words with a stick figure on the outside of his house.

He said it was there for a very short time on a wall that was to be demolished, and he did it in response to a function following a Court of Appeal decision when he thought the David Bain case had been put to rest forever. Mr Weir told the court it was the result of a lot of stress during the Court of Appeal process, but admitted it was unreasonable and inappropriate.

David Bain's lawyer has also accused the former detective of planting evidence during the initial murder enquiry.

The court has already heard of a glasses lens found in Bain's younger brother Stephen's room, and glasses frames and another lens in David Bain's room. Mr Reed has shown Mr Weir, who found the lens, a series of photos of the area, with one showing a gap where the lens was later found.