a skeleton in the closet

いつもは読んだ英文の中から見つけた覚えたい単語・表現を取り上げていますが今日は最近のニュースを聞いていてふと思い出した英語の表現についての復習です。
家族の白骨遺体が見つかる事件が次々と報道されていて、日本人のモラルはどうなっているのかと驚き、嘆いていましたが、昔覚えた英語の慣用句に "a skeleton in the cupboard "/ "a skeleton in the closet" があるのを思い出しました。　辞書の説明を幾つか次に紹介します。
・McGraw-Hill Dictionary of American Idioms and Phrasal Verbs:
a hidden and shocking secret. You can ask anyone about how reliable I am. I don't mind. I don't have any skeletons in the closet. My uncle was in jail for a day once. That's our family's skeleton in the closet.
・UsingEnglish.com
If someone has a skeleton in the closet, they have a dark, shameful secret in their past that they want to remain secret.
・GoEnglish.com:
"Skeletons in the closet" are things about your past which you would prefer not to tell to other people. Example: "He's a very popular senator but he will never be elected president; he has too many skeletons in the closet." Years after a person has died, only the skeleton remains, and a skeleton of bones can be a frightening thing to look at. "Skeletons in the closet" are embarrassing things which we would like to put away so other people cannot see them. Example: "I don't want anything to do with that guy; he has too many skeletons in the closet." Example: "I had only known her for one week. How could I know what skeletons she had in her closet?"
・Englishclub.com:
a skeleton in the cupboard/closet
Meaning: If you have a skeleton in the cupboard, or in the closet, you have a secret in your past which could damage you if it became known.
For example: Before we give you the job, we need to know if you have any skeletons in the cupboard which the press could find out about. Things like a criminal record or drug or alcohol problems in the past.
Politicians can't afford to have any skeletons in the closet these days. Their enemies are sure to find them.
Note: "A skeleton in the cupboard" is used in British and Australian English while "a skeleton in the closet" is used in American English. The meaning is the same for both.
"a skeleton in the closet"は普通は比喩で使われているようですが、西洋でも実際にこの様な事件があったからできた表現なのでしょう。
追記：　同じ様な説明をくどくどといくつも羅列していますが、この表現を忘れないための手段なのでご容赦願います。