There is an identically-titled Sherlock Holmes short story written by Sir Arthur Conan Doyle in 1891. However, the short story plot elements are not being used.
Ken Marks has played four different characters over the course of the series:
- Episode 3.8 End of Watch (2014) - Moderator
- Episode 2.21 The Man with the Twisted Lip (2014) - Meeting Leader
- Episode 2.7 The Marchioness (2013) - Chairman
- Episode 1.2 While You Were Sleeping (2012) - Moderator