Bones fans were in for a shock when a beloved character said goodbye for the last time on the premiere of the series' tenth season. But showrunners had a good reason to write the character off the hit show.

(Spoiler alert for those who have not yet watched the season premiere entitled, "A Conspiracy of Bones," continue reading at your own risk.)

FBI psychologist, Lance Sweets (John Francis Daley), on the popular Fox show has met a gut-wrenching end. He is the first regular character on Bones to be killed off.

The death comes as a shock to fans because his character was reuniting with former girlfriend, Daisy (Carla Gallo), and it was revealed that she was pregnant with his child.

But the show had been leading up to a dramatic moment of this scale with the conspiracy story arc that had been plaguing the FBI since last season.

Daley's character was already taking a leave from FBI duties and working with inner street kids in order to give him time to work off the show to direct the reboot of National Lampoon's Vacation, which he co-wrote with Jonathan M. Goldstein. But since filming was pushed back, new arrangements had to me made for the character.

According to series showrunner, Stephen Nathan, rather than have Sweets appear on a show in a string of guest appearances, they decided to give him an exit that would make a big emotional impact.

"It was a devastating thing for us to do. We were in a strange situation and wanted to find out how best to handle it - and we wound up handling it in the most painful way imaginable," he said.

Even Daley shed some tears after the cameras stopped rolling and he was zipped up into the body bag for his final shot. The episode wrapped up filming a month before airing and they were happily surprised that news of the character's demise was not leaked online.

The death of Sweets actually shows the confidence that Bones writers and producers have for Daley to continue getting work as a successful director even after he finishes working on Vacation.

Daley said that although he is sad about leaving Bones, where he spent most of his professional career and his 20's working, the departure allows him to follow his dream to be a director as well as an actor and writer.

He already has a string of hit screenplays on his belt, all written with his co-writer Goldstein, such as The Incredible Burt Wonderstone, Cloudy with A Chance of Meatballs II, and Horrible Bosses.

The new National Lampoon's Vacation film is set to star Christina Applegate, Chris Hemsworth, and Ed Harris.

Although Sweet's death was a dark note to open the tenth season of Bones with, the team assures fans that the lighthearted romantic comedy tones of the show will be back soon as they build momentum for the much-anticipated 200th episode of the series.