In the final episodes of Bones season 9, it may be revealed that the elusive Ghost Killer is not an actual person at all.

Bones executive producer Hart Hanson spoke with TVLine this week about the Ghost Killer and whether or not he or she is just a psychological construct for Brennan (Emily Deschanel).

"The Ghost Killer plays heavily through the end of this season," executive producer Hart Hanson revealed. "But does this killer exist, or is it the one last paranoia that Pelant [Andrew Leeds] left behind? That is the question. And is that the world's best camouflage, that this person might not exist?"

The Ghost Killer began haunting Brennan's dreams in the season 9 midseason premiere, appropriately titled The Ghost in the Killer.

Bones Season 9 Spoilers: 'Young and the Restless' Star to Become New 'Squintern' at the Jeffersonian

Meanwhile, the producers of Bones are in the process of negotiations with Fox for a potential 10th season, and some of the story lines for the next season are already being plotted out.

"When we get an official pick-up [for Season 10], we're going to know one way to go [storyline-wise]." Hanson said when asked about storyline potential for Dr. Sweets (John Francis Daley). "And if we don't get a pick-up and it's the last season - which I don't think will happen, but you have to ready for anything - we have another way to go. That's not necessarily applying to Sweets, but anyone's future could be in flux."

Bones Season 9 Spoilers: Sweets Goes Undercover as Hodgins Discovers Family Secrets [VIDEO]

Bones season 9 airs Fridays at 8 p.m. on Fox.

Watch the trailer for the next episode of Bones here:

Tags: Bones Spoilers