The collection on sale as "Marilyn Monroe -- Last Sitting" had an estimated value of between $18,000 and $25,000 at the Bonhams auction. However, the lot "failed to meet its reserve price", spokeswoman Julie Saunders Guinta said.

The photographs were taken by Bert Stern during a marathon session for Vogue magazine and caught the screen queen unclothed, holding a champagne glass and lounging in bed. One shows Monroe topless and facing the camera with her arms in the air.

Monroe was found dead in her bed in August 1962. The coroner said she suffered a sleeping pill overdose and her death was considered to be probable suicide. Persistent conspiracy theories suggest that she was murdered.

Cult-like interest in the dead actress and sex symbol feeds a mini industry, including frequent discoveries of yet more previously unseen photos.