Quantico: Will Alex locate the second bomb before it goes off? Caleb's mysterious past revealed

Quantico is nearing its midseason finale and new suspects are emerging, who could be responsible for the deadly Grand Central station blast. In the previous episode, Alex Parrish, who is being framed as the prime suspect of the explosion, surrenders before the FBI to prevent another bomb from going off at an unknown location in New York and to save her boyfriend Ryan Booth from the bullet injury he received while escaping from the FBI.

The episode also revealed the truth about Caleb and his possible connection with a Scientology-like institution. "I won't say definitively that it's Scientology," executive producer Joshua Safran told TVLine. "But we definitely want to look at all aspects of sort of all institutions, I would say, that make up America — whether that's religious institutions, whether that's financial institutions, whether that's governmental institutions," he added.

In the previous episode, Caleb has some proof that could prove Parrish's innocence, but even before he could produce it, the runaway agent surrenders before the FBI. While sneaking into his father Clayton's emails, Caleb discovers a chain of mails -- one of which was sent by his father's assistant -- confirming that an agent at the New York field office has noticed that another agent used Parrish's FBI badge to gain entry into the Grand Central station.

Moreover, Safran also teased that Alex would find support from another high rank authority in her struggle to prove her innocence. "In the very next episode, the question of who in the upper ranks of the FBI is on Alex's side — and who is definitely not — is very clearly answered," he told the website.

It will be interesting to see whether Alex will be able to stop the other bomb from explosion and how she will escapes from the FBI's prison again to find the mastermind behind the deadly blast. Quantico airs at 9pm CT on Sundays on ABC network.