One day, a diamond was stolen. Detectives came to the scene and asked the owner of the diamond to tell what happened. He said: "Five people came to see the gems today. Before they entered the diamond room, my secretary brought them five glasses of wine and ice. When we entered the diamond room, the diamonds were gone. Before that, there was a lady named Alice who looked at the gem." The detective thought about it and came up with the answer.
I = D, D = I
Do you know who stole the diamond?