In Dr. Jekyll and Mr. Hyde, the antagonist of the story has a dual personality. While being Mr. Hyde, he engages in wrongdoings. However, he adopts a completely different attitude while being Dr. Jekyll.
After a series of crimes, Utterson follows Jekyll's Butler, Mr. Poole, to his house after claims that Jekyll had no come out of his laboratory for weeks. After arriving, he goes to the laboratory only to find the body of Mr. Hyde in Jekyll's clothes.
"Evil can never truly hide" relates to the quote "The truth is always known." Since the beginning of the story, the reader had the impression that there was something sinister which was being hidden.
