Jon Snow HBO

Warning: There are spoilers ahead if you're not caught up with "Game of Thrones."

HBO just released an ominous first teaser poster for "Game of Thrones" season six, and it's doing exactly what the network wants - to get fans talking about the show's biggest mystery once : Is Jon Snow alive or dead?

At the end of season 5, Jon Snow was left for dead after a mutinous attack by his Night's Watch brothers. Since then, fans have been in an inescapable debate of whether or not Jon Snow has been permanently killed off the HBO series.

Many of those working on the show, from producers to actors to the president of HBO programming himself, have insisted he's dead and never coming back.

But die hard fans refuse to believe the claim.

Theories of Jon's survival have been circulating ever since 2011, when the last book, "A Dance With Dragons," was released. When the show finally caught up to the books in season five, TV viewers joined in with wild speculation. We wrote up a lengthy overview explaining theories of how Snow could still be alive right after the season five finale. The short of the argument is that Melisandre, the red priestess, will probably revive Jon through a fire-magic ritual that has precedent in the series.

But at this point, fans are looking beyond the books for clues. Instead, they've turned to denouncing every statement and action made by those involved with the show's production. These are the top six reasons fans are refusing to believe Jon Snow is totally dead.

1. The semantics game

Michael Lombardo HBO TCA tour 2015 Getty Images

When asked plainly if Harington was released from his contract, showrunner Dan Weiss told Entertainment Weekly: "Dead is dead." The director of the finale episode, David Nutter, also told President Obama himself "Jon Snow is deader than dead."

The latest insistence came from HBO programming president Michael Lombardo. "Dead is dead as dead as dead. He be dead. Yes. From everything I've seen, heard, read, Jon Snow is indeed dead," he said.

This may have dispelled casual watchers from believing the hype, but the zealots have continued to brush these off as lame cover-up attempts. When you look at these quotes back to back, it's almost comical how intent everyone is on using the words "dead" and "Jon Snow" in the same sentence.

This brings us to the semantics-based argument that devoted followers have begun circulating.

Sure. Jon Snow may very well be dead. BUT, he's most likely going to be resurrected or reborn next season. Technically, HBO can put word out there that he's "dead" without being deceptive.

Because, really, what else would HBO representatives say? "Well, you've figured it out! You're right, he's totally coming back." Of course not. They have to try and maintain some semblance of mystery, however thinly veiled.

game of thrones jon snow season 5 Jon Snow was Lord Commander of the Night's Watch when his subordinates stabbed him in revolt Helen Sloan/courtesy of HBO

Just minutes after the season five finale, Entertainment Weekly ran an interview with Kit Harington, the actor who plays Jon Snow. When asked about the possibility that his character might not truly be dead, Harington was adamant. "They said, 'Look, you're gone, it's done.' If anything in the future is not like that, then I don't know about it - it's only in David and Dan and George's heads. But I've been told I'm dead. I'm dead. I'm not coming back next season."

Blowing right past the insistence that he is dead, readers latched onto the technicality of that last sentence. So Harington isn't coming back next season. Does that mean he may come back the season after that? Some fans think so.

If anything, Harington's comments just put internet detectives on alert for potential news of his appearance on set for the next season. "Game of Thrones" works on a tight schedule. Just weeks after the season five conclusion, actors and crew members began assembling in one of the set locations, Belfast.

2. #HairWatch is in full effect

Kit Harington Harington looks awfully comfortable with his untrimmed hair at Wimbledon Getty Images

Harington's precise location isn't the only detail that fans are obsessing over. The length of his hair has become a focal point of many believers.

In December 2014, The Independent reported Kit Harington regretted being contractually obligated to keep his hair long for the role of Jon Snow. Harington said he planned to "cut it off quite soon. As soon as I'm allowed." If he truly isn't returning as Jon, and has fulfilled the HBO contract, surely he'll turn up with short hair. And yet, week after week, every photo snapped of Harington shows those long locks intact.

Above is a photo taken in early July, when Harington attended Wimbledon and created a hair-related frenzy of speculation.

Each one of his appearances in Belfast has inspired fans to reassure their co-conspirators that his hair has undergone no changes.

3. A "quite spectacular" slip

Melisandre Season 5 Melisandre may be the key to Jon Snow's return next season HBO

Carice Van Houten, the actress who plays Melisandre and Jon Snow's would-be savior, said in an interview after the finale aired "you feel that [Melisandre] is concentrating more and more towards Jon Snow … there are slight hints that something's going to happen." These words had a much more dramatic implication coming after Harington's statements regarding the finality of his death.

Van Houten also teased that something "quite spectacular" was in the works for next season, but she wasn't able to elaborate.

It feels as though Van Houten is referring to the hints fans have grabbed onto as a basis for their theories that Melisandre will be involved with Jon's return from the dead. One commenter pointed out, "She's not being terribly subtle."

4. The telling history of San Diego Comic-Con

game of thrones robb stark Robb Stark's murder was one of the more heartbreaking moments of the series so far HBO / Helen Sloan

The final clue that fans have focused on came from the highly-anticipated "Game of Thrones" panel during the 2015 San Diego Comic-Con. These panels often feature both of the show's creators, David Benioff and D.B. Weiss, as well as several prominent cast members who were killed off in the most recent season.

In 2013, the panel included Michelle Farley and Richard Madden; the actors who played Catelyn and Robb Stark, respectively. Their deaths at the Red Wedding massacre in season 3 were among the most shocking and game-changing of the entire series.

Then, in 2014, the fan favorites Rose Leslie (Ygritte) and Pedro Pascal (Oberyn Martell) were also present at Comic-Con. Ygritte was Jon Snow's love interest, and had been killed during a battle at the Wall. Oberyn Martell had an iconic death against the Mountain. Both were on hand for the "Game of Thrones" panel to answer questions about their experiences on the show.

When the 2015 panel participants were announced, dedicated followers immediately noticed three major absences. Both show creators AND Kit Harington were missing from the line-up. This sparked plenty of conversation around the logic behind this decision, and whether it was a clear move on HBO's part to avoid direct questioning about Jon from fans.

5. The incomplete "In Memoriam" toy collection

In Memoriam Game of Thrones Toy Collection store.hbo.com

Mid-July, HBO announced a new collections of "Game of Thrones" character merchandise. The group of toys was dubbed: "Honor the Fallen: Game of Thrones™ In Memoriam." The tribute includes the likes of Stannis Baratheon, Oberyn Martell, and Ned Stark.

Jon Snow was noticeably absent from the set.

More conspiracy conversations were sparked from this HBO announcement. Since many iconic characters were included, why not Jon? Perhaps it's because his death is not as permanent as the those who were included.

6. Snow has been spotted on set

jon snowe game of thronesHBO.

Popular "Game of Thrones" news community Watchers on the Wall has reported multiple sightings of Harington among cast members in Northern Ireland. They referred to Jon's return as "the worst-kept secret in Game of Thrones land."

The argument can be made that he is merely on set to film a funeral scene, but this isn't entirely convincing for one reason: Back in September, Harington was spotted on the show's set in Northern Ireland - and it was no funeral being filmed.

Watchers on the Wall claims Harington was seen filming a big fight, one where he may be leading Northern armies against the Bolton family.

As of November 16, the site reports there is a scene being filmed between Snow, his sister Sansa, Ramsay, and Littlefinger.

The fact remains that, as far as anyone has been informed, only three individuals actually know whether Jon Snow is alive or dead. The author of the book series, George R.R. Martin, and the two creators of the HBO series David Benioff and D.B. Weiss. Martin has reportedly told Benioff and Weiss how the series ends, which means they should know Jon Snow's true fate.

Until the series returns - or author George R.R. Martin publishes the sixth book, "The Winds of Winter" - dedicated followers of both the book series and the show are stuck in an frustrating but hope-filled purgatory.