Three previously unpublished short stories by reclusive author J.D. Salinger have leaked online.

The Catcher In The Rye writer withdrew from the public eye after the huge success of his only published novel and ceased releasing his work in 1965.

He protected his privacy until his death in 2010 and left instructions that his unpublished works should not be seen for 50 years following his passing.

However, a scanned copy of three of Salinger's unpublished works was uploaded to a file-sharing website by an anonymous user this week (beg25Nov13) under the title Three Stories and it has quickly spread online.

The original manuscripts of the three tales - The Ocean Full Of Bowling Balls, Paula and Birthday Boy - are kept under lock and key at two university libraries in the U.S.

Book critic David Ulin is convinced at least two of the three stories are genuine, writing in the Los Angeles Times, "I've never read The Ocean Full of Bowling Balls. It's part of a collection of Salinger material at the Princeton University Library and available only to scholars who are supervised as they read. I have read the other two stories, however, at the University of Texas' Ransom Center, and the versions of them in Three Stories are the real deal."

A Princeton University spokesman says, "The story (The Ocean Full Of Bowling Balls) is probably an unauthorised version transcribed longhand in our reading room. It's also possible that it came from photocopies of the typescript probably made before the mid 1980s when we decided we'd no longer allow photo-duplication for any work by Salinger."

The Ocean Full Of Bowling Balls is said to be an early version of The Catcher In The Rye, written for America's Vanity Fair magazine, but withdrawn before publication. The story is narrated by the brother of Holden Caulfield, the teenage character in Salinger's later book.