Aisha Tyler is taking center stage on Criminal Minds.
On Wednesday's episode, titled "Mirror Image," Tyler's character, Dr. Tara Lewis, is targeted by Mr. Scratch, one of the remaining serial killers at large that the BAU team has been chasing. He grabs her attention by kidnapping her brother and sending a man under his spell, Desmond Holt (Alimi Ballard), to play the part of Dr. Lewis' missing sibling.
The episode, directed by series star Joe Mantegna, is a slight departure from the usual procedural elements that make the CBS crime drama tick. As Tyler explains, exploring Dr. Lewis' backstory, family history and why she has a vested interest in serial killers was a mandate the writers always intended to delve into.
"It was the extension of a conversation with [executive producers] Erica Messer and Breen Frazier when they first brought me on the show," Tyler, who also divides her time on The Talk and Archer, told ET. "We did talk a lot about who she was and where she might have come from, with the hope and intention that if I was ever there longer, we'd get to explore it. So it was great to dive into that stuff."
Tyler said it was refreshing to dig into the inner workings of her character's psyche for an episode -- even though it was "intense" at times.
"I think it was nice. In a lot of ways it was intense, but at a different pace. It was less procedural, it was less situational, it was more about these people's relationships and I couldn't have a better guy to do that with than with Joe," she said.
The scenes with Ballard and Stan Shaw, who plays Dr. Lewis' father, were the ones Tyler marveled over the most, calling them "incredible." ET exclusively premieres a scene from Wednesday's episode, in which Dr. Lewis breaks the devastating news to her dad that her brother has been kidnapped.
"There was a lot of subtlety and a lot of subtext because we have a character who's my father and another character who believes he is my brother, and we were interacting like a family unit, even though we weren't," Tyler said.
The latest episode also marks the first time new BAU unit chief Emily Prentiss (Paget Brewster), will have full reign over the team, officially taking over for the departed Aaron Hotchner (Thomas Gibson).
"It's sensational. She had such a great history with the show, with the BAU, as an actor and also as a character, and we were all so excited by the idea. We were all texting each other and getting fired up when it came up," Tyler said of the team's new head honcho. "We're all so proud of [Paget]. She's an amazing person and it's a great character and it makes perfect sense for the show and the dynamic of the team."
In next week's fall finale, Criminal Minds will welcome another team member, seasoned profiler Special Agent Stephen Walker, who will be played by new series regular Damon Gupton.
"There have been a lot of changes over the last couple of years and he fit in seamlessly," Tyler shared. "He's an incredibly talented guy, a pro, lovely to be around and a very different presence than what we've had previously. He adds a different dynamic to the team. Everybody is humming along, which is nice."
Criminal Minds airs Wednesdays at 9 p.m. ET/PT on CBS.