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Line of Duty returned to our screens last Sunday with its long-awaited sixth season - and already, it looks as if AC-12 are in for a tense ride.
The series starts with the anti-corruption team in disarray, with Kate Fleming (Vicky McClure) having left the unit altogether, Steve Arnott (Martin Compston) bored stiff, and Ted Hasting's (Adrian Dubar) reputation in tatters.
But it seems - despite being entirely torn apart after the events of Season 5 - that the team are still committed to catching "bent coppers", with their enquiries now focusing on Joanne Davidson (Kelly Macdonald) after her unconventional handling of a murder investigation.
While the jury's still out on whether Joanne is genuinely "bent", some fans believe there's a connection between our new prime suspect and the events that happened in Season 5.
Line of Duty viewers will remember the scenes of Joanne returning to her Fort Knox-esque flat towards the end of the first episode of Season 6, with the numerous locks on her doors suggesting she's at risk of harm from an Organised Crime Gang (or OCG, if you're up to date with the Line Of Duty lingo).
However, it was the photograph she looks longingly at while necking a glass of wine which got the more astute fans scratching their heads.
Despite stating earlier in the episode that she has "no family", a photo on Joanne's flat sees a younger Joanne cuddling up close to a woman who looks remarkably familiar.
The woman looks an awful lot like Anne-Marie McGillis, the former police informant and mother to John Corbett - who fans should remember as the undercover officer (played by Stephen Graham) who turned into full-blown gang member last season before his throat was slit in shocking scenes.
Their similarities have seen some fans propose that Joanne could very well be John's sister - which would certainly make for a jaw-dropping twist if true.
Fans flocked to Twitter to discuss their detective work.
"So when I was watching Line of Duty, I saw this picture and immediately thought of Anne-Marie McGillis?! Surely?!" exclaimed one fan. "Can I join AC-12 now?"
"Could Davidson be Corbett's sister?" asked another when clocking the photo.
"I'm calling it now, Davidson is going to be Corbett's sister," said a third.
A fourth added: "Am I completely off or did anyone else think that photo in Davidson's flat looked like Corbett's ma from series 5?"
The plot thickens...
We can expect yet another huge signature Line Of Duty twist this season, with the show's executive producer Simon Heath confirming there will be a scene in this year's series that will "break the internet".
How are we going to contain ourselves?
Line of Duty continues at 9pm on BBC One.
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