I went back to the site of the mystery suitcase. It was still there and someone else had broken the edge of the locked case. (I wouldn't have done that!)
When I looked inside it was empty but a rolled up calendar from 2003 had been in it. Perhaps something else was here as well but taken by the person(s) who opened it.
I think the mystery was more fun than the apparent truth! Are the curious readers satisfied?? (Click picture to enlarge it)