"Line of Duty" series 4 air date is fast approaching and a big question has been bugging the minds of viewers; who is Balaclava Man?

According to Digital Spy, "Line of Duty's" Balaclava man is the masked killer who is responsible for the kidnap and assassinations of at least three women. Aside from that, he was also the one accountable for the devastating assault on the audience's beloved Steve Arnott (Martin Compston).

Nevertheless, it is yet to be seen who is behind the mask. But then, as of the moment; the avid viewers know that the suspect is the one with a Y chromosome.

To decode the mystery, The Telegraph has theorized who is the person behind Balaclava Man in "Line of Duty." The first among the list is Michael Farmer (Scott Reid) as during the whole series it was believed that he was the serial killer.

It was also speculated that Nick Huntley (Lee Inglebly) was behind the mask; but during the climax of last week's "Line of Duty" episode, he deafeningly protested his innocence. Huntley's lawyer; Jimmy Lakewell (Patrick Baladi) also become one of the possible Balaclava Man since he arrived on-screen in the previous chapters of the series.

The creepy forensic co-coordinator Timothy Ifield (Jason Watkins) was also speculated as the masked murderer since he claimed that Farmer was innocent. So perhaps, he may be the one who is guilty with the crimes committed.

ACC Derek Hilton (Paul Higgins) was also theorized to be behind "Lind of Duty's" Balaclava Man as he admitted last week that he was the station chief starting from series one when the frozen body parts were features in another exploitation case. With this, untrustworthy Hilton may really believe that AC-12 is no longer fit for purpose or maybe he has an ulterior reason to shut down the crusading internal affairs team.

It also makes sense for Balaclava Man to be a cop as DC Jamie Desford (Royce Pierreson) or DS Neil Tyler (Mark Stobbart) being the main candidates. Apart from the aforementioned names and characters, it was also suspected that an anonymous criminal behind the masked killer in "Line of Duty."

To know who really is behind Balaclava Man; the avid fans should not skip watching "Line of Duty" series 4. The episode will air this Sunday; April 30 at 9 PM on BBC One.

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