Anyone who complained that this series of Line Of Duty had so far lacked the pace and excitement of previous seasons were forced to eat their words as the BBC cop drama continued on Sunday night.
In scenes nearly as dramatic as the much-celebrated series three finale, the AC-12 crew were ambushed while convoying a witness – none other than Jimmy Lakewell, the corrupt legal firm partner we last saw in series four, who was part of a cover up in Operation Trapdoor.
But no sooner had we got reacquainted with the slimy solicitor, he met his maker at the hands of another returning character, Lee Banks.
The episode also put to bed one popular fan theory that had suggested DI Kate Fleming was actually deep undercover for AC-12, with only Superintendent Hastings aware of her mission.
However, a scene between them revealed that she really did choose to leave anti-corruption after the investigation into Hastings’ conduct tarnished their reputations.
While viewers got an answer to that burning question, there were a whole lot more to be answered by the time the credits rolled. Here’s the ones we’re asking this week...
1. Do we believe Buckells?
As we’ve previously mentioned, we already know it was DCI Davidson who was actually responsible for the gap in surveillance at Beechwood House. However, DSU Buckells’ interview with AC-12 certainly furthered the theory he could have still been in league with organised crime, despite various bits of evidence being planted by Davidson.
We can’t be the only ones who thought of Tommy Hunter and The Caddy when golf clubs were seen in a picture of his car boot where the missing Vella files were found?
Former OCG boss Hunter was regularly seen on the golf course in series one, and his love of the sport was where DI Matthew ‘Dot’ Cottan, AKA The Caddy, got his nickname.
While we definitely think Buckells is dodgy, it’s to what degree that we are still unsure about.
The clubs in his boot could have been shown to throw us off the scent, and while he obviously colluded with Lee Banks in Jimmy Lakewell’s murder, his nervousness could also suggest he was coerced.
2. Has Davidson known who Pilkington really is all along?
There were various knowing looks between Davidson and OCG member PC Ryan Pilkington prior to the revelation that he had been traced at various places she had also been.
Pilkington later threatened Davidson at her home when she informed him she would have to release him from MIT due to budget issues.
While Pilkington’s intentions are now abundantly clear to Davidson, had they previously been having meeting outside of work? If so, it would suggest Davidson has known who he really is all along.
3. Is Chief Constable Osborne ‘the fourth man’?
Back in series one, Philip Osborne covered up what happened in the killing of Karim Ali.
As background, Ali was wrongly identified in a counter-terrorist police raid, which DS Arnott was a part of, and shot dead. Back then, Osborne was working as the team’s Chief Inspector and ordered his officers to lie about what happened in their statements. Arnott refused to co-operate and went to AC-12, leading to him being hired on the team. Despite Arnott testifying against his former colleagues, no officers were prosecuted for their actions.
In the present day, Osborne has now risen to become the Chief Constable of Central Police, and we learned that he has ordered the slim-lining of anti-corruption operations following Hastings’ decision to charge Buckells.
While we already know Osborne is corrupt, he hasn’t yet presented any links to organised crime. However, it is definitely suspicious he has ordered cuts to anti-corruption just as they were making huge strides in their work. Could he actually be ‘the fourth man’, who is at the very top of the force?
4. What case was Vella working on?
As many fans had already guessed, the mystery man that journalist Gail Vella had interviewed about police corruption prior to her death was Jimmy Lakewell.
During the interview, Lakewell referred to a second case that had a racist element, with AC-12 deducing that this must have been the case Vella followed up on and that could have led to her murder – but what is it, and who is involved?
5. Did Lakewell tell Arnott about the case prior to the ambush?
Scenes in the van after AC-12 picked up Lakewell from prison saw Arnott further questioning Lakewell about what he’d discussed with Vella.
While he pointed out anything he said would be inadmissible as evidence, the action cut away before anything else was said.
Later, when Lakewell returned to AC-12 HQ to be formally interviewed, he refused witness protection, remained silent and asked to return to prison. However, there was a suggestion he had actually filled Arnott in on the details back in the van, so Lakewell’s subsequent death doesn’t necessarily mean the lead has gone cold.
6. Will Davidson throw Fleming under the bus?
With Fleming on to Pilkington, she’s covertly tried to warn Davidson about the danger he poses to her, but she is insistent on him remaining on the team as – unbeknown to Fleming – she is now being blackmailed by him.
In order to get Fleming to drop her crusade against Pilkington, Davidson threatened to report the fact Fleming had not called it in when she was suspicious about Terry Boyle’s police escort.
Given she’s already in cahoots with AC-12 over Pilkington, Fleming is now caught in a very sticky situation indeed.
7. Who tipped the OCG off about the Lakewell plot?
The ambush of Lakewell’s police convoy gave us the most dramatic moment of the series so far, but it led to one of the series’ biggest questions too – just who tipped off the OCG about it?
As Hastings and Arnott noted, it could be explained by a prison officer the OCG had on the payroll, or – as DC Bishop pointed out – it could also have been someone from inside AC-12. Does the department have another rat in its ranks?
It’s also worth picking up on the point the team made about the ambush being a sophisticated operation, so the order must have come from the top.
Could that top dog be someone like, ooh we don’t know, Chief Constable Osbourne, perhaps?
8. Why is Lee Banks back?
We last saw OCG member Lee Banks in series five when Hastings visited him in prison, and now he’s back in the story having killed Lakewell in his cell upon his return to Blackthorn.
Banks was another character who we guessed we might not have seen the last of, as he was central to one of the loose ends the series five finale didn’t tie up.
If you cast your mind back, there were questions about whether Hastings was actually the one who had leaked information about undercover officer John Corbett’s real identity to Banks, which led to his death.
Under questioning, Hastings lied about ever visiting Banks, but AC-3 boss DCS Patricia Carmichael was still convinced he’d blown Corbett’s cover. She was unable to prove it when DCC Wise insisted the case against Hastings was shut down.
Could Banks’ reappearance suggest Hastings’ conduct – and his mysterious relationship with Corbett’s widow Steph – will be further explored?
We also haven’t forgotten that he shares the same surname as Carl Banks, one of the prime suspects in Vella’s murder, either.
9. Who is Davidson related to?
Following a further forensic investigation into PS Jatri’s home, AC-12 were able to establish that Davidson had lied about ever living there as her prints were present.
Furthermore, it was discovered that her DNA sample was a match to someone already known to anti-corruption – someone who it turns out is also a blood relative of Davidson’s.
While we’re going to have to wait a week to find out the identity of Davidson’s mystery relative, you’ll remember that she lied to Jatri about her family in the first episode of the series, claiming not to have any. She later returned home and became angry while looking at a picture of what appeared to be her with a family member.
So whoever this relative AC-12 have discovered turns out to be, we’re guessing that they have a very complicated relationship with Davidson.
While we face an agonising wait to find out who they are, some fans already have a major theory about their identity.
Line Of Duty continues on Sunday at 9pm on BBC One.
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This article originally appeared on HuffPost UK and has been updated.