Spoilers follow for last night's The Walking Dead...
Last night saw Glenn apparently killed off, which has caused the internet to erupt with outrage as well as suspicion that Steven Yeun isn't done just yet.
While some of it as best circumstantial:
Glenn's death wasn't shown on screen, and the death scene left an "out" for Glenn to surive (watch here)
Steven Yeun didn't appear on Talking Dead as every actor that gets killed off appears on the episode following their death
Talking Dead didn't include Glenn's death in their look back eulogy
There is a strong piece of evidence that indicates Glenn didn't die, which comes from the The Walking Dead set located in Atlanta as Steven Yeun has been spotted filming many scenes that have yet to air following the death scene:
As we see, Glenn is spotted with "Jesus," a character that has yet to surface this season. The Spoiling Dead Facebook page futher suggests Glenn is not dead as they state there have been lots of Steven Yeun sightings on set -- more than likely not indicating a red-herring or flashback scene:
We have soooo many sightings of Glenn after episode 3 in multiple episodes. I just can't see [The Powers That Be] getting Steven to continue to come out to filming sites and stay there for multiple hours just to throw off a small percentage of fans that follow spoilers. He's even been at locations that were blocked off and extremely difficult to get actor sightings.
What may be going on is that the "death of Glenn" is just more or less hype for the series and this Sunday's big 90-minute episode. Obviously, the producers of The Walking Dead know how things go when a character is killed off and changed things up on The Talking Dead to bring about the question whether or not Glenn is really dead.
It's even possible the ruse may have started back in July at the SDCC, as Norman Reedus replied "Glenn" when asked what cast member they would like to bring back, which caused mixed reaction from the other cast members and Greg Nicotero (via Huff Post):