Fun fact Apt pupil has a reference to Shawshank where the main character says he lives off stocks that a banker setup named Dufresne who went to prison for murdering his wife.

King does this all the time in his stories having character connections across different novels, making them set in the same universe. Fun, adds some depth to all of it. Like Randal Flagg being the same villain in the Stand and the Dark tower and Eyes of the Dragon.