Line of Duty SPOILER: A first look at the sixth episode shows Steve Arnott coming to the filming scene

The sixth season of Line Of Duty left fans with more questions than answers, and viewers flocked to Twitter to ask what DCI Jo Davidson actually does, did Kate Fleming really leave AC-12 and who is H?

Here MailOnline examines some of the most prominent fan theories

Kate Fleming has NOT left AC-12 and is working on a secret mission

One of the most shocking revelations was that Kate AC-12 is now working with a new team – and some fans suggest she could even be the infamous X.

As she chatted with her new DCI Davidson gaffe, Kate said, “I ate a spicy copper, I’d rather go after the lunatic who killed Gail [Vella]. ‘

But despite seeming confident of their new role, some viewers wondered if everything was okay and theorized that Kate could still be a secret to AC-12.

Even after she tipped Davidson and drew the wrath of Ted Hastings, fans continue to speculate that she is so deeply secretive that even Hastings must keep her true agenda a secret.

Kate Fleming has NOT left AC-12 and is working in secret: Is that true? The jury has not yet been selected for this one

DCI Jo Davidson is blackmailing the Organized Crime Group

Jo has already survived a barbecue from the best AC-12 team and seems to have erased her name when it looks like PS ex-girlfriend Farida Jatri was involved in corruption.

However, Jo is seen driving with the famous bent copper Ryan Pilkington and taken away to collect a phone with a burner, making her once again suspicious.

Fans, however, are convinced that DCI was blackmailed by OCG, after her emotional outburst when she was invited to take a new burner.

DCI Jo Davidson Blackmails Organized Crime Group: Is That True?  After her outbreak in the parking lot, it seems more and more probable

DCI Jo Davidson Blackmails Organized Crime Group: Is It True? After her outbreak in the parking lot, it seems more and more probable

DCI’s mother Jo Davidson is Anne-Marie McGillis

Fans have been speculating who Joa’s mother might be after she was seen in the photo in the first episode.

Many theorized that her mother had something to do with the character of John Corbett from the fifth season [Stephen Graham] mother of Anne-Marie McGillis, who was killed by an Irish Republican paramilitary group shortly after 1989.

DCI’s mother Jo Davidson is Anne-Marie McGillis: Is that true?  There just isn’t enough evidence yet to determine on the road or whatever

DCI’s mother Jo Davidson is Anne-Marie McGillis: Is that true? There just isn’t enough evidence yet to determine on the road or whatever

Gail Vella is still alive

Although the sixth season focuses on the murder of journalist Gail Vella, one vague theory is that she is actually still alive.

Craig Parkinson, who played Matthew ‘Dot’ Cotton in the show, told the BBC Sounds podcast Obsessed Line of Duty: ‘Someone is in that apartment and there is some connection to Gail Vella, an investigative journalist.

‘You don’t throw someone like Andi Osho, and then just add small magazine prints to it and stick them on the kitchen wall.’

Sarah Millican – who also appeared in the podcast – further suggested that Vella may have been a former mistress of DCI Davidson’s.

Gail Vella is still alive: Is that true?  It seems unlikely that the scale of police corruption is so large that they could pretend to be a murder victim

Gail Vella is still alive: Is that true? It seems unlikely that the scale of police corruption is so large that they could pretend to be a murder victim

DC Chloe Bishop is the daughter of Tony Gates

Bishop is one of the newest rookies of the AC-12, and as Gates and his wife Jools got two daughters, Natalie and Chloe, viewers suggest that their common name “can’t be a coincidence”.

Gates ’daughter was last seen in the first season of 2012, meaning she would have been around the same year as Bishop.

Fans have suggested that Bishop either took her mother’s maiden name or stepfather’s name, so her true identity remains a secret for now.

Gates died at the end of the first season when he entered a busy road after receiving a confession from gang leader Tommy Hunter, who blackmailed a police officer to cover up their criminal activity.

DC Chloe Bishop is the daughter of Tony Gates: Is that true?  The dates and facts agree, but there is still not enough to write it off by accident

DC Chloe Bishop is the daughter of Tony Gates: Is that true? The dates and facts agree, but there is still not enough to write it off by accident

The mysterious blood relative of DCI Jo Davidson is …?

After it was discovered that Join DNA matched someone on the police national computer, fans theorized who it might be.

The prevailing theories suggested that Davidson’s cousin was Tommy Hunter, from the first and second series, Mike Dryden from the second, John Corbett from the fifth series, or Derek Hilton, killed in the fourth series.

Tommy Hunter was the leader of OCG in earlier series of shows and a pedophile. His character is dead.

Mike Dryden, a former deputy chief of police, was last seen resigning from the post for perverting justice in the second series. His Scottish connections also suggest he could be related to Davidson.

John Corbett was a secret cop in the fifth series whose throat was cut, leaving behind a wife, two daughters and a mysterious relationship with his wife Anne-Marie, who fans claim could be Davidson’s mother as well.

Derek Hilton was the Chief Superintendent and later the Assistant Chief of Police of the Central Police. He was also secretly connected to organized crime. He was shot in the mouth during a staged suicide in the fourth season.

Other suggestions were Gill Biggeloe, Jackie Laverty, Lindsay Denton or Terry Boyle.

After it was discovered that Join DNA matched someone on the police national computer, fans theorized who it might be.  Scottish Mike Dryden was last seen resigning for perverting justice in the second series

After it was discovered that Join DNA matched someone on the police national computer, fans theorized who it might be. Scottish Mike Dryden was last seen resigning for perverting justice in the second series

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