While the intense mystery of who framed Alex (Priyanka Chopra) continues on ABC's "Quantico", we will see the unravelling of more information with regards to her parents, and the relationship between her mother and father.

As we already know, a lot of what is happening to Alex is closely related to her father â€“ whom she shot to death- and his history with the FBI. It is understood that in Episode 4 "Kill", Alex will uncover some unexpected facts, which will help her understand more about her parents' relationship.

In "Kill" we will also see Alex questioning how trustworthy all her classmates actually are. In her investigation to find out the truth behind the terrorist attack, she finds out that one of her classmates may not be that innocent. Could the traitor be Simon?

In the promo clip, Alex is seen pointing a gun at Simon and asking, "You lied to me the whole time?" He has been her ally so far, and it seems like Simon was actually playing her. Simon is seen speaking on the phone with someone who asks him to "keep her there", possibly referring to Alex. Simon replies that she trusts him and that he would be able to get more information out of her.

Read More: Alex, Simon uncover FBI's darkest secret; Who are Nimah, Raina?

In the promo, Alex is also seen in a physical altercation with Shelby (Johanna Braddy), who warns Alex that she cannot outrun the FBI. She tries to get Alex to give up, and seeing as there is a "shoot on sight" order for her, Alex might just have to give in to Shelby's demands.

In the flashback scenes, we see Alex questioning her abilities after a hostage rescue exercise. Completely shaken, she decides to quit, but as we all know, she will be sticking around, only to be charged with terrorism.

Watch out for Season 1 Episode 4 of "Quantico" at 10.00pm (EST) on Sunday, 18 October, on ABC. You can also live stream "Kill" via ABC Go!