The suspect behind the attempted murder of Morland has a link to Holmes and Watson in the upcoming episode 23, titled "The Invisible Hand," of the fourth season of the procedural drama "Elementary."

After Sherlock Holmes and Dr. Watson find out that the perpetrator behind the attempted murder on Sherlock's father Morland, they discover an unexpected link to themselves.

In the promo trailer for "The Invisible Hand," Sherlock believes that Moriarty is not the one behind Morland's attacks. However, it seems like his greatest nemesis will return. The clip also shows what looks like a shooting in NYPD. Morland is also seen shouting at Sherlock to stop lying to him. Dr. Watson asks Sherlock if there is someone he trusts; Sherlock responds by saying he trusts her.

In other related news, actor Johnny Lee Miller explained on New York Post why his character Sherlock do not have and will not have a romantic relationship with partner in crime, Dr. Watson. He said, "Holmes and Watson's relationship is sacred, and if you change that, then the show is not about Holmes and Watson anymore."

He added that just because Sherlock is a man and Watson is a woman, it does not mean they have to be together. What's important, he said, is "who they are as people." Since the pair on the original story is not involved romantically, there is no need for them to be have a more-than-friends relationship on the show as well.

Meanwhile, here is the rundown of the previous episode, titled "Turn It Upside Down."

The identity of the person behind the complex web and the attack of his father was finally revealed. It was none other than Moriarty herself, who loves creating complicated plots. Also, Sherlock's mother is mentioned once again, which could mean that his father might have kept something from him about the ring.

"Elementary" season 4's penultimate episode airs on Sunday, May 1, at 10 p.m. on CBS.