The only criminal aspect in this case is that someone allowed a major oil painting by this great 19th-century British painter to deteriorate to such an extent that it was a 'wreck' when two Canadian restorers bought it to experiment on in their studio. They soon realised, however, that something special lay beneath the garishly-overpainted surface.
Having tried unsuccessfully to match their image - a misty river valley with rainbow arches and rainy clouds - to other Turners, they turned to the Royal Canadian Mounted Police, who, using sophisticated technology, matched the smudged fingerprints on the restorers' picture with other Turner prints found on his 1828 Chichester Canal in the Tate Gallery in London.
The painting is now being studied by David Hill, head of fine art at University College, Bretton Hall, in Wakefield, West Yorkshire. He believes that on stylistic grounds, it may be a Sussex scene - although, he said, such shallow valleys can be found almost anywhere in England.
Researching it will be a lengthy process: apart from matching the subject to actual views, he will be comparing it to other Turners. Considering that the artist left 500 oils, 2,000 watercolours and more than 20,000 sketches 'it will be like looking for a needle in a haystack', Dr Hill said.
But the clinching evidence may well lie in the fingerprints. Dr Hill, who intends to have further tests done, will be approaching West Yorkshire Police for help.
There are numerous prints to compare them with. Dr Hill explained: 'Turner used his fingers to paint. He smeared out the paint with his finger . . . often very vigorously.'