The Best Way Out Is Always Through - S3-E22
Continuity mistake: When Bell and Holmes are looking at the files, there's an open book next to Bell. When he starts texting, with both hands, the book becomes closed in one shot and then back open in the next.
Chosen answer: M broke into the brownstone and left a note. Holmes deduced he was staying at a high-class hotel from the soap scent on the note, and gave a picture from a hidden camera to his "irregulars" on the street to stake out hotels. One of them saw him, so Holmes followed him to his next intended victim and knocked him unconscious with a baton.
Sierra1 ★