The story below is to help answer the question

The Strange Case of Dr. Jekyll and Mr. Hyde is written mostly in the third-person by a narrator who is not a participant in the story but who narrates the story from the limited perspective of a supporting character, a lawyer, Mr. Utterson. In other words, the reader knows only what Mr. Utterson knows. However, in the final chapter of the novella, the first-person point of view of the protagonist emerges through the literary device of a letter addressed from the protagonist to Utterson. This use of the first-person point of view in the final chapter is crucial to the understanding the full meaning of the novella's events and ending the suspense that has been building up during the course of the plot. In the letter, the protagonist tells his life's story from its beginning until the time of the novella’s conclusion: “I was born in the year 18 — to a large fortune, endowed besides with excellent parts, inclined by nature to industry, fond of the respect of the wise and good among my fellow-men, and thus, as might have been supposed, with every guarantee of an honorable and distinguished future.” In this way, the protagonist solves the mysteries of the novel as he tells his story using the first-person point of view (“I”) for his confession.

How does the plot create suspense in Robert Louis Stevenson’s The Strange Case of Dr. Jekyll and Mr. Hyde?