Trigger Point viewers are doing some investigating of their own and think they've spotted a 'definite baddie'.
But it's not just the one as a second character has set alarm bells ringing.
Episode four of the new ITV drama aired on Sunday night as the search for the terrorist group responsible for various attacks on the capital continued.
After sharing the evidence she found in the locker of her colleague, John, Lana couldn't keep it together long enough and confronted him in front of her bosses.
READ MORE: ITV Trigger Point viewers distracted during intense Billy scenes as Lana's brother is set up
'Wash' accused him of grooming her younger brother, Billy, who had been carted off to the police station after smashing the window of a Halal butchers.
But her outburst left her being instructed to take personal leave.
She then headed to see military man Karl who has become a source of comfort as she works alongside her boyfriend, Thom.
Lana, however, was soon called for help when she got a call from her bosses telling her they believed Billy was a member of the terrorist group after being caught with a recently killed member of the same group.
They roped Lana into calling her brother and when he finally answered with the ploy his sister was with his ex-girlfriend.
Billy soon discovered he had been set up and he wasn't picking up his mates at all and that his car was rigged with a bomb outside a tube station in the middle of a protest.
He was soon directed to a playing field where the police and bomb squad were waiting.
Lana then arrived at the scene and tried to calm her brother down as she figured out the best course of action and to help save her brother.
But as a timer on a device ticked down, Billy panicked and tried getting out the car when it burst into flames.
While Billy doesn't appear to be involved in the group behind the attacks, viewers have pointed out two people they think could be - and they're those closest to Lana.
@KathW80 tweeted: "Oh my god! Thom said ‘you did the right thing bringing this to me’ he is 100%, odds on, definitely definitely a baddie - that line is in the top 10 of the evil undercover baddies’ playbook #TriggerPoint Stay away from his fancy flat, Lana! @Vicky_McClure."
"Thom is DEFINITELY a wrong-un #TriggerPoint," @kirstyplank said.
But @KellyHarding01 said: "Is Karl or Thom the bad guy… one of them has to be the baddy, right? I called Thom at the start but now I’m confused #TriggerPoint What an incredible actress @Vicky_McClure is!!"
"Lana needs a break! Karl or Thom are surely in on this? #TriggerPoint," @rosecoloredchar echoed.
@amisha1982 asked: "Which one is dodgy then - Karl or Thom? One of them must be #TriggerPoint."
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