2000: Art theft was 'professional' job
Police have said the Cezanne painting taken from the Ashmolean Museum in Oxford on New Year's Eve was probably stolen to order.
The painting - Auvers-sur-Oise - was bought by the Ashmolean in 1980 and is said to be worth £3m.
It was the museum's only work by French impressionist Paul Cezanne and was integral to their collection of art from that period, which included works by Monet, Van Gogh and Picasso.
Superintendent John Carr of Oxford Police said: "Whoever has taken this painting has given some thought to how to steal it. The person has some reason for it and some outlet for it."
Thieves entered the gallery through the glass roof, via scaffolding around a new library extension being added to the building.
The Ashmolean, which is the oldest public museum in the world, maintains that its security systems did not fail. But the thieves used smoke canisters to set off fire alarms and cause enough confusion to escape with the prized landscape.
Museum director Christopher Brown said: "Cezanne played an absolutely key role in the representation of a key period in 19th century painting and it really is a great blow to us and the way in which we can display that moment in Western painting."
Police are circulating details of the painting internationally in the hope that its whereabouts can be traced. They are also appealing for any New Year revellers that witnessed anything suspicious on the night of the crime to come forward.
The work is an oil on canvas depicting a group of small, white cottages in a lush, tree-filled valley. It was framed and measured 18 by 22 inches.