Readers may remember this column talking about a drawing which was recently attributed to Leonardo da Vinci on what seemed very convincing grounds and which some experts have accepted as authentic.
There are developments. Doubt has been cast on the attribution.
The work is a profile portrait of a young woman in ink and coloured chalks on vellum which had previously been thought to be by an unknown 19th-century artist, perhaps German.
It was seen at a Christie's auction in New York in 1998 by a Mr Peter Silverman, who was unsuccessful in bidding for it, the drawing going to a New York dealer, Kate Ganz, for $US21,850.
In 2007, Mr Silverman saw it again, it later became clear, in a drawer in her shop.
Thinking it might be a Leonardo, he bought it for about the same amount on behalf of a Swiss friend.
He then tried to prove his hunch and a forensic art specialist, Peter Paul Biro, of Montreal, examined it.
Mr Biro said a fingerprint on it was like one on an indubitable Leonardo, thought to be that of the master himself.
There was also a palm print indicating it had been worked by hand, as Leonardo did.
These and more conventional pieces of evidence were considered by Martin Kemp, professor of art history at Oxford University, an authority on Leonardo's scientific work.
Prof Kemp became convinced and has published a book.
It has been said if the drawing is authentic it is worth $US150 million ($NZ206 million).
The first dent in the story appeared a while ago, but it was highlighted by an article in the British newspaper The Daily Telegraph on April 12 this year.
Apparently, the discoverer, Mr Silverman, first announced he had seen the work in a drawer at his Swiss friend's place, not the New York dealer's.
The dealer, Ms Ganz, scotched this by faxing a copy of the invoice to The New York Times, where the story first appeared, showing Mr Silverman had bought the drawing from her.
The paper published a correction, but the incident seems significant.
Mr Silverman had said his friend didn't know who the artist was.
While it occurred to him it might be Leonardo, he didn't dare to mention it, or Leonardo's name.
But Ms Ganz's label described the drawing as obviously based on a number of paintings by Leonardo da Vinci.
This certainly suggests Mr Silverman likes a good story ... and the information impairs his credibility.
But there were others involved in this case.
As we saw, Prof Kemp had come to believe in the drawing's authenticity.
In March this year, his book was published supporting that view.
It was co-authored by Pascal Cotte, who gave technical arguments in favour of the conclusion.
The preface was written by Nicholas Turner, a former curator of drawing at the British Museum and the Getty.
The Telegraph article, written by Richard Dorment, described the book as advocacy, not art history.
His account of a conference about the drawing makes it sound as much a media event as a serious discussion.
There are people with serious credentials in Leonardo studies who have supported the attribution.
But there are others, equally impressively qualified, who have dismissed it out of hand.
But then there's the forensic fingerprint evidence, which in this case seemed to trump the traditional use of documents and connoisseurship.
On July 12 this year, a long article by David Grann appeared in The New Yorker raising serious questions about it.
Mr Grann met Mr Biro, the specialist who examined the fingerprint on the drawing and said it was Leonardo's.
An investigation of his past revealed he had been the unsuccessful defendant in a number of cases brought by former clients concerning works of art whose attributions by Mr Biro, or their provenance - their former ownership - had been questioned.
Even so, Mr Biro had made a name for himself authenticating works by significant artists, using the fingerprint method.
Some had been attributed to Jackson Pollock, the American abstract expressionist painter, relying on a print Pollock left on a paint can.
Mr Grann got a fingerprint expert to examine prints on a painting attributed to Pollock by Mr Biro.
The expert examined the one on the can and concluded the ones on the painting were forged.
Mr Biro has denied this and questioned the expert's expertise.
He never handled the Leonardesque drawing so he couldn't have planted its fingerprint.
Nevertheless, his identification of it has been questioned.
Ambitious attributions are contentious and there are some very murky people in the art world.
But this doesn't determine who made the drawing or redefine the relationship between science and judgement.
Peter Entwisle is a Dunedin curator, historian and writer.
