When Detective Cassidy refers to Richard White as "Mr. Jekyll and Dr. Hyde," he is mocking White, not misquoting Robert Louis Stevenson. Cassidy is alluding to White's professional side being the monster, not the personal side that sends flowers and feels guilty.
During the final interrogation (the last minute or two of the episode), the boom mic is reflected in the interrogation room mirror.
When interviewing Richard White's business partner, the boom mic is reflected in the mirror (approx. at 25 min).