When where and how was Anne Frank's diary found?

Anne Frank received her diary in 1942, and wrote in it - and a succession of other diaries - until August 1, 1944. On August 4th, they were arrested, and immediately after the arrest, Miep Gies gathered up Anne's diary and put it - unread - in a drawer of her desk, intending to give it back to Anne after the war. When Anne did not come back, she gave it instead to Otto.