Girl in Sunlight by Rupert Bunny.
The mystery began on an autumn night in April 1991, when a burglar broke into the Blairgowrie home of elderly retiree Albert Watt.
According to the police report, the only item stolen was Mr Watt's cherished Rupert Bunny painting, Girl in Sunlight, which hung above his dining table and is worth about $250,000.
Mr Watt bought the painting - which depicts a woman with a white parasol reading in a Parisian garden - in 1953 and kept it in his South Yarra apartment until his sea change in the late 1970s.
Police never solved the theft, which they described as ''targeted''. Over the years, Mr Watt would blame his cleaner - the only person who regularly admired the painting - while his nephews, James and Michael, assumed it ended up overseas. Mr Watt died in 1993, two years to the day after Girl in Sunlight was taken, with the case unsolved.
As executors of their uncle's will, Michael and James Watt continued the search, offering a substantial reward and even engaging a private investigator, but to no avail.
Eventually, an anonymous phone call ended the mystery. That call came in 2010, when the National Gallery of Victoria held a retrospective of Rupert Bunny's work. Girl in Sunlight was scheduled to go on display.
The tip-off led police to the Malvern East home of Frank Levy - the new owner of the painting - and the discovery that it had apparently been stolen by Mr Watt's closest friend, Peter Rand. Mr Watt and Mr Rand - an eccentric millionaire property investor and rumoured Melbourne brothel owner - were South Yarra friends and neighbours for more than 40 years.
But now, according to court documents, it has been established that Mr Rand was the likely mastermind behind the theft.
Mr Rand kept the painting until his own death in 1997. According to his will, Mr Levy - his lawyer - would receive a ''painting by Rupert Bunny of a woman sitting on the ground''.
The Levys did not know the painting had been stolen, displaying it in their Malvern East home for the next decade.
In February 2008, Mr Levy and his wife decided to have the painting valued. The valuer told them art historian and curator David Thomas was cataloguing Rupert Bunny's work for an exhibition at the NGV and would be interested in seeing the painting. A few weeks later, Mr Thomas decided to include the work in the NGV's retrospective.
In April 2010, the matter was reported to police and a few weeks later a search warrant was executed at Mr Levy's home. But that wasn't the end of the battle for the Watts. Their uncle's painting had been found, but Mr Levy argued that the statute of limitations had expired and the Bunny was now rightfully his.
For the past three years, the case has been before the Supreme Court. Last week Mr Levy finally lost his appeal.
Twenty-three years after Girl in Sunlight disappeared, the painting is once again with Mr Watt's heirs.