[ ruò yào rén bù zhī，hú fēi jǐ mò wéi ]

要想人家不知道，除非自己不去做。指干了坏事终究要暴露。

汉·枚乘《上书谏吴王》:“欲人勿闻，莫若勿言；欲人勿知，莫若勿为。”

If you don't want anyone to know, don't do it (idiom). fig. If you do something bad, people will inevitably hear about it.