Criminal Minds' sixth season has been most notable so far thanks to the sad departure of J.J., but that's not the only surprise in store for fans of the hit procedural.

TV Guide reports that there are some secrets yet to be revealed involving the BAU members themselves - specifically, Reid, whose upcoming story line "is a doozy."

Executive producer Simon Mirren says that Spence is hiding a secret connected to his "genetic past." This and other unraveling plot lines will carry the weight this year.

"Some of them are very emotional, and some of them are very simple," says Mirren, who's also writing a special Garcia episode. "Garcia's is not a depressing secret."

"You will really get to see another side of Garcia that we haven't seen in six years of working with her, and it's kind of shocking in one way and fantastic in another."

Especially with J.J. gone, this is good news for fans worried about the loss of the show's human element. Which character(s) would you like to see fleshed out more?

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.