Season 1 Episode 9 of "Quantico" was monumental in that we saw Alex (Priyanka Chopra) turning herself in to the FBI and Liam (Josh Hopkins) finally believing in her innocence. However, Liam felt that the only way to catch the real bomber was for the FBI to publicise Alex's arrest, and hence, we saw her pleading guilty in "Guilty".

The episode had also raised a few suspicions regarding her classmates Shelby (Johanna Braddy) and Simon (Tate Ellington). "Guilty" saw the arrival of a new coach at Quantico, Dr Susan Langdon (Anne Heche). She is a former agent whose expertise lies in catching serial killers, and she imparted her knowledge to the NATs via a test.

Although Simon's team, of which Alex was a part, solved the case seemingly correctly, Simon was sure they were wrong. When he confronted Susan, she threatened to kill him, but was saved in the nick of time by Ryan (Jake McLaughlin). Simon went ahead and filed a case against Susan, claiming she messed with the evidence to solve the case, allowing for the killer to be let out.

When his classmates found out what Simon did, they were all angry about his action. Livid, Simon decided to set a plan in motion. It required the blueprint to all railway stations in New York City, which is more than shady, considering Grand Central Station was bombed just weeks after that.

However, making Simon the real bomber at this point would be too obvious, and we are looking at another person who is likelier to be the real terrorist.

All fingers point towards the director of the Quantico training programme, Miranda, who seemingly helped Alex escape. Her part in the attack seems logical because of her history with Liam, the repeated blaming of Charlie (J Mallory McCree), her son, and the secrecy in bringing the twins (Yasmine Al Massri) to the academy.

It is quite obvious she is still in love with Liam, and in one of the previous episodes, she is seen telling him to stop helping the woman he loves, most possibly Alex, who seems to have got really close to him in "Guilty". She also has a connection to Alex's past that has not been revealed to us as yet.

Other fans theorise that "Quantico" may just be another huge test that acts as the final frontier for the NATs to pass before they become full-fledged agents. However, that does not make sense, considering the amount of mass destruction and lives lost in the attack.

The ultimate twist in the plot would be to show Alex as the real bomber, and her playing all the games to get away with it with the help of her unsuspecting classmates. Regardless, we will get to see who Alex thinks the bomber is in the upcoming episode. 

Watch Season 1 Episode 10 of "Quantico" at 10 pm (EST) on Sunday, 6 December. You can also live-stream "Quantico" via ABC GO!