Joyce Hatto was a pianist of some note who retired from performing back in 1976, to fight cancer. She lived a good long time after that retirement and enjoyed a degree of notoriety in the last decade of her life due to the release of a wide variety of new recordings on her husband William Barrington-Coupe's tiny label Concert Artist. As the story in Gramophone puts it

To love Hatto recordings was to be in the know, a true piano aficionado who didn't need the hype of a major label's marketing spend to recognise a good, a great, thing when they heard it.

Gramophone followed up, first by asking a human classical expert to listen to the two. When that expert claimed no difference they sent the two discs to an audiologist, who found them identical. The story linked above has more details, including what appears to be a deliberate digital manipulation of at least one track to conceal its origins.

Wikipedia is keeping a "current event" section as people add information on recordings and possible sources. There appears to be evidence of what can only be classed as a massive fraud.

In some ways this is not a new story - people plagiarize and have for centuries. This caught my attention because of the involvement of iTunes and the role of digital "fingerprints" in the automatic identification of works.