'Criminal Minds' Season 12 Finale spoilers: Derek finds a lead that could help them catch Mr. Scratch in 'Red Light'

Criminal Minds star Shemar Moore RTX2QSH2 — Actor Shemar Moore poses at the 2016 amfAR Inspiration Gala in Los Angeles, California U.S., October 27, 2016. REUTERS/Mario Anzuoni

"Criminal Minds," starring Joe Mantegna (David Rossi), Matthew Gray Gubler (Spencer Reid, Ph.D.), A.J. Cook (Jennifer "JJ" Jareau) and Aisha Tyler (Dr. Tara Lewis), will have an upcoming episode titled "Red Light," which will be the crime drama's 12th season finale. It will show Derek Morgan (Shemar Moore) finding a lead that could help the team catch Mr. Scratch. Below is the latest "Criminal Minds" episode guide.

Spoiler alert: This update contains more 'Criminal Minds' spoilers. Read on only if you want to know more about the upcoming episode.

"Criminal Minds" Season 12, episode 22 features Reid squaring off with an archenemy from the past that has resurfaced. According to a CBS press release, Reid has no choice but to do so when he is caught in an impossible situation. Meanwhile, Mr. Scratch, a fugitive that has proven to be extremely elusive for the Behavioral Analysis Unit (BAU) team, may finally be caught when Derek discovers an important lead.

'Criminal Minds' cast 2017 and 'Red Light' guest stars

"Red Light" was directed by Glenn Kershaw and written by Breen Frazier. The other "Criminal Minds" cast members including Paget Brewster (Emily Prentiss), Damon Gupton (Stephen Walker), Kirsten Vangsness (Penelope Garcia) and Adam Rodriguez (Luke Alvez) will be seen in this episode.

According to the Internet Movie Database (IMDb), Bodhi Elfman (Peter Lewis), Beth Riesgraf (Dr. Maeve Donovan) and Jane Lynch (Diana Reid) will also appear in "Red Light." Gia Mantegna (Lindsey Vaughn), Kevin Will (John Fords), Richard T. Jones (Guard Lionel Wilkins), Ellington Ratliff (Ronnie Hawks), Calvin Harrison (Agent Cal) and Cynthia Rose Hall (Guard) will join them as guest stars in this episode.

'Crimina Minds' episodes

'True North' recap

The episodes before "Red Light" were "True North" (US airdate: April 5), "Unforgettable (US airdate: April 26) and "Green Light" (US airdate: May 3). "True North" was directed by Joe Mantegna and written by Bruce Zimmerman. It showed a case that involved three decomposing bodies of college students that were tied to wooden stakes outside Tucson, Arizona. Plus, Lewis also convinced Reid to take a cognitive interview that led to a surprising twist.

'Unforgettable' recap

"Unforgettable" was directed by Carlos Bernard and written by Stephanie Sengupta. It featured Reid being visited by his mother and another person from the past. Meanwhile, Walker's friend got hospitalized after ingesting a radioactive material. The BAU team found a connection between the incident with Walker's friend and the deaths of some government employees.

'Green Light' recap

"Green Light" was directed by Alec Smight and written by Erik Stiller. It showed Reid being temporarily freed from prison to help the BAU team find his mum, who has been kidnapped by Lindsey Vaughn, an abduction victim from the show's Season 3. It was revealed in this episode that Cat Adams (Aubrey Plaza), a freelance hitwoman from Season 11, was behind all of it, including the frame job, not Mr. Scratch. She demanded that Reid visit her at the women’s correctional facility in order to find out where her accomplice Lindsey is holding his mum.

"Criminal Minds" airs in Australia on Seven. It is aired in the US on Wednesdays at 9-10 pm on CBS. The "Red Light" episode airs on May 10.