AceShowbiz -

"The Walking Dead" leaves us with a new mystery following the airing of the midseason finale. In "Hearts Still Beating" that aired Sunday, December 11, someone wearing muddy boots was watching Rick and Aaron from afar as the two collected guns from the boat house.

The same person, whose face was unseen, was later seen spying on Father Gabriel in Alexandria on the post-credits scene, as Rick, Michonne, Carl and Tara were making plans with Maggie and others at Hilltop.

This sparks a speculation that "The Walking Dead" will soon introduce the Whisperers. The comic book characters are known for spying from a distance and moving quietly through the woods. They disguise themselves with roamer skin to blend in with walkers.

Asked about the mysterious person in the midseason finale, the comic book writer Robert Kirkman kept his lips sealed. "I really wish I could tell you," he said on "Talking Dead", but promised that it would be revealed soon.

"All I can say is that those boots, you'll definitely recognize those from earlier-they're connected to that boat scene-and you know," he added, "that's a big part of what we're dealing with when we come back next half of the season, so we'll be revealing that soon. It's going to be a great half season."

"The Walking Dead" returns with the second half of its seventh season starting February 12 on AMC.