While fans are still waiting to hear more details about the return of "Sherlock" in 2017, speculations continue to circulate regarding the possible return of the ruthless Jim Moriarty (Andrew Scott) in the fourth season of the British crime drama series.

During the season 2 finale, Moriarty killed himself in order to urge Sherlock Holmes (Benedict Cumberbatch) to commit suicide. But after his death, he continued to haunt the legendary detective. In the third season finale, a video showing Moriarty's face was broadcasted all over Britain. In the clip, he kept repeating the statement: "Did you miss me?" Then in the special "Sherlock" episode titled "The Abominable Bride," Sherlock's mortal enemy visited him in his dream.

While Moriarty continues to be a part of Sherlock's life even after his death, series co-creators Steven Moffat and Mark Gatiss have yet to confirm whether the character will return in the show's upcoming season.

Other speculations claim that a third Holmes brother will be introduced in "Sherlock" season 4. According to reports, actor Tom Hiddleston is in the running to portray the role of Sherlock and Mycroft Holmes' (Gatiss) other brother named Sherrinford. However, the series co-creators and Hiddleston remain mum about the issue.

Meanwhile, lead actor Benedict Cumberbatch hinted that "Sherlock" could exist beyond season 4.

"I'm still enjoying it. We'll see how the next series goes, but as I've said many times before, I'd love to keep ageing with him. Martin and I started this relatively young compared to a lot of Holmes and Watsons, so why not?" the actor said in an interview with Radio Times.

Cumberbatch also mentioned that special episodes such as "The Abominable Bride" could continue if it will be difficult for the show to have a regular season.

The fourth season of "Sherlock" is expected to return on screen in January 2017.