"Criminal Minds", television's No. 1 suspense thriller, is all set to return with Season 11 this month. Now, CBS has released a premiere trailer that reveals a few key plot details, including a mole in BAU and the bizarre case the team's trying to solve. The trailer also introdues the new member, Dr Tara Lewis (Aisha Tyler).

The first new promo of the upcoming season teases Hotch and shows the team working on a very twisted and bizarre case that involves them dealing with a criminal, who overwhelms his victim silently and then injects them.

This is in line with what showrunner Erica Messer had hinted at during an interview with TVLine. "This UnSub does some, obviously, weird stuff to his victims, which includes painting their faces. And then we learn why he's doing it, because he himself has a really hard-to-look-at face," she had said.

Even CBS had hinted earlier that BAU will chase a serial killer who has left evidence behind, suggesting that it is someone determined to take revenge.

In addition to this, Hotch can be clearly heard as saying that someone tipped off the killer and there is a mole in the BAU team. Now, who could that be?

Well, we know the team very well to be suspecting anyone, but there's a huge possibility that it could be the new team member, forensic psychologist Dr Tara Lewis. Isn't it a very obvious prediction? If it's none of the old members, it has to be the newbie.

We don't think that the showrunners will give it away that easily. Moreover, we know that one more BAU team member will leave the show, so, it's quite possible that it's the mole who will be asked to leave.

The promo teaser also introduces the newly-appointed psychologist Dr Tara Lewis, who has come in to fill in for Jennifer Jareau (AJ Cook). In the promotional clip, Lewis, who is helping the team crack the case, is seen explaining her reasons for joining BAU.

Now, will Dr Tara Lewis be able to prove her worth? We will learn whether the mole is caught or not in the premiere of "Criminal Minds" Season 11 on CBS at 9 pm on 30 September.