ZURICH (Reuters) - Swiss federal prosecutors have dropped an 11-year investigation of suspected money-laundering by Egyptians related to the Arab Spring uprisings, they said on Wednesday.

       "Despite the numerous enquiries and having transferred 32 million Swiss francs to Egypt in 2018, the Office of the Attorney General (OAG) must now accept that the investigation has been unable to substantiate suspicions that would justify the indictment of anyone in Switzerland or any forfeiture of assets," the OAG said in a statement.

       It said it would release the remaining 400 million Swiss francs ($429 million) that had been frozen.

       The Swiss inquiry began in 2011 following events related to the protests which led to the downfall of long-time Egyptian leader Hosni Mubarak.

       The "complex and extensive" criminal case initially involved 14 suspects, including Mubarak's two sons, as well as 28 persons and 45 legal entities whose assets were seized. Five suspects had remained under investigation, the OAG said.

       The original suspects, most of whom held official or important economic positions in Egypt, were thought to have used Switzerland to launder the proceeds of corrupt acts.

       ($1 = 0.9315 Swiss francs)

       (Reporting by Michael Shields; Editing by Hugh Lawson)