His return had been teased months earlier without giving away the tragic context, and according to A.J. Cook, she was the one who reached out to her former co-star to see if he could come back after conversations with showrunner Erica Messer. On the subject of what it was like to be back on set with Gubler, Cook told EW:

“I’m still mad,” A.J. Cook says of that devastating loss for JJ on Criminal Minds.

Matthew Gray Gubler returned as Dr. Spencer Reid on the May 22 episode of Criminal Minds: Evolution A.J. Cook (Jennifer "JJ" Jareau) opened up about how Gubler's "brief" but "impactful" cameo came to be in an interview Gubler starred on all 15 seasons of Criminal Minds' original run,