Something that a person would never do is spoken of as if it were an object the person wants put far away from him. Alternate translation: "It is not like me to do something like that" (See: [[rc://en/ta/man/jit/figs-metaphor]])
Here "hand" stands for the whole person. Also, "was found" can be stated in active form. Alternate translation: "The man who had my cup" (See: [[rc://en/ta/man/jit/figs-synecdoche]] and [[rc://en/ta/man/jit/figs-activepassive]])