Fans continue to wonder when they might learn more about the upcoming series 4 of BBC's "Sherlock," but they have had little to satisfy their curiosity. The season is unfortunately not expected to be released until 2016 due to the difficulty of scheduling its long, intensive filming in the calendars of very successful and busy actors like leads Benedict Cumberbatch (Holmes) and Martin Freeman (Watson), said series co-creator Mark Gatiss in during a question & answer session in Brazil, the Mirror reported.

Season 4 Clue (Spoiler Alert)

Series 3 of BBC's "Sherlock" left fans to speculate if Moriarty really died. Could this mastermind have staged the event? They were also left with the question of whether Janine might possibly reunite with Sherlock, even if she got mad at Sherlock in Series 3 after learning that she was used by Sherlock to get near to Magnussen. Writers Gatiss and Steven Moffat have hinted elsewhere that Moriarty is very much alive and that there may be a third Holmes brother.

The last episode of Season 3 revealed that Mary was carrying Watson's child, which gives her the reason to hide her real identity and provides a loose thread that it is unlikely will be overlooked in Season 4. She and he may be drawn closer if consequences come from him destroying evidence of her identity.

Sherlock's Series 4 will still have Cumberbatch and Freeman reprising their roles as William Sherlock Scott Holmes and Dr. John Watson, respectively. Others in the cast include Jonathan Aris, Vinnette Robinson, Andrew Scott, Jalaal Hartley, Clive Mantle, Lars Mikkelsen, Louise Brealey, and Una Stubbs. Watson's former love interest Jeanette may yet return to the show, hints actress Oona Chaplin during an interview with RadioTimes.com. "It is his loss, he doesn't know what he is missing," she said, adding that she could still return to the show. "You never know."