TRIGGER Point fans believe they have rumbled who the secret double agent could be within the extremist terrorist group after a huge “giveaway” clue.
The third episode of the ITV show - which stars Line Of Duty actress Vicky McClure as bomb disposal officer Lana Washington - aired yesterday evening and fans are convinced they've worked out a big twist for Lana's family.
The ex-military officer has been hot on the tails of the extremist group for days, but is still struggling to put the pieces together as to who is behind the horrific crimes.
As the organised group prepare for their next attack, eagle-eyed viewers believe that her brother has a part to play.
It comes after Lana visited his apartment where he was acting rather shifty and made a constant effort to keep the curtains closed.
As she made herself at home she said: "You're not a vampire, Billy. You can open the curtains you know?"
As he shielded his eyes away from the light, he exclaimed: "Lana keep them closed! Do us a favour, yeah? Don't mention this to mum and dad."
And fans couldn't help but share their suspicions on her reclusive brother as they flooded to Twitter to post their theories online.
Alongside an emoji of a surprised face, one person wrote: "I have a feeling the brother has something to do with the bombings on Trigger Point."
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Echoing their comments, someone else said: "I'm putting it out there now. I think her brother is part of the bad group."
A third person added: "I'll be surprised if Lana's brother isn't somehow involved with the group behind it all - and she'll end up having to defuse a bomb that's linked to him."
Trigger Point continues on Sunday at 9pm on ITV.