'Criminal Minds' Season 15 Premiere Preview Teases Return of Killer They've Encountered Before

Ahead of the 15th season premiere for Criminal Minds, the show is hinting at the return of a well-known killer the team has a history with. The sneak peek for the upcoming episode shows a meeting of the Behavior Analyst Unit's minds to discuss the similarities between a trio of recent murder victims. Knowing that they were all stalked through a dating app, David Rossi (Joe Mantegna) seems convinced that this means Everett Lynch is back, although the rest aren't so sure.

Despite evidence to the contrary, Rossi is not only convinced they're dealing with the handiwork of Lynch, but he's specifically acting out to catch his attention. Even as the rest of the BAU try and lay out the facts that point away from Lynch's direction, Rossi remains unmoved and is seemingly determined to resume his vendetta against the serial killer.

Lynch, who's also known as The Chameleon, is a psychotic killer, arsonist, con-artist and misogynist who first appeared in last season's episode, aptly titled "Chameleon." The character only appeared in flashbacks throughout, and was portrayed by Castle star Michael Mosley.

In "Chameleon," Lynch is almost caught after he's chased by Rossi from the scene of a crime. However, Lynch ends up ambushing Rossi and choking him unconscious, only to leave a carving in his forehead and the knife he did it with as a reminder that Lynch let him live.

While Lynch remains at large, it's clear that Rossi is determined to put Lynch behind bars -- even if the facts of the case don't add up to his particular MO.

This isn't the first time Lynch's name has come up in relation to the show's 15th season. Back in July, Daniel Henney, who plays Matt Simmons, brought up the character by name and stressed that he isn't the run of the mill bad guy that Criminal Minds has contended with.

"Overall, I'd say [Season] 15 has more of an arc through the episodes than previous seasons," Henney told Watch! magazine. "Our unsub, Chameleon, he's definitely into some gruesome, creepy stuff."

In addition to Lynch's return, the show's Season 14 finale ended on something of an emotional bombshell when it was revealed that J.J. (A.J. Cook) may be in love with Reid (Matthew Gray Gubler). Showrunner Erica Messer addressed that plot point last month to TV Line, explaining that the two characters "have been in the trenches together — as far as work goes, it's life or death quite often — and who are we to say who gets close and who doesn't?"

Messer also conceded: "Yeah, it's messy and it's weird, but 'I've loved you for a long time'... that's just the truth."

Season 15 of Criminal Minds kicks off tonight with a two-hour premiere at 9 p.m. ET on CBS.