A recent report from Wales Online has confirmed that the BBC series "Sherlock" will begin production for season 4 at the Pinewood Studios this coming spring and that the show is expected to premiere by January 2017. The series will likely air by New Year's in the U.K. and will air via PBS in the U.S. a few weeks after.

Pinewood Studios has been home to previous seasons of the popular show, indicating that many familiar locations from the previous three seasons will make a return in season 4. However, the most recent New Year special "Abominable Bride" was shot in Bristol. 

The studios have also been used for many high-profile Hollywood films such as "Star Wars: The Force Awakens" and the "Harry Potter" franchise. 

While it is certain that Benedict Cumberbatch and Martin Freeman will be on set to reprise their roles as Sherlock Holmes and Dr. Watson, respectively, there are now rumors spreading across the Internet that season 4 may also bring back Moriarty (Andrew Scott).

According to a report from the Korean Portal, a Reddit user explains that hints of Moriarty's return have been planted throughout the "Abominable Bride" special episode. In particular, these clues include the use of the words "Redbeard," "Scarlett Roll" and "611174."

"Redbeard" is a referrence to the dog that the Holmes family once owned but had to be put down. The "Scarlet Roll" is explained as a complex riddle referring to a red herring. There is also the fact that Sherlock stated "I never said he was alive. I said he was back."

Putting two and two together, these clues hint that Moriarty may be returning soon. The character could indeed be dead but there are always the possibilities of other villains using Moriarty's image as a part of their offensive against Sherlock, Watson and the local police.