Egypt’s chief prosecutor on Wednesday ordered the transfer of former President Hosni Mubarak from a Cairo military hospital back to prison. Mr. Mubarak is expected to be held there pending a retrial on charges including complicity in the killing of protesters during the 2011 revolt that toppled him. He had been in the hospital since December after injuring himself during a fall in the prison shower, his lawyers said. The prosecutor ordered the transfer after Mr. Mubarak appeared Saturday in a Cairo courtroom, where, despite being on a gurney, the former president appeared in good health and high spirits, waving to supporters. A medical board subsequently ruled that Mr. Mubarak was well enough to be sent back to prison. A judge scheduled May 11 as the date for the new trial.