Line of Duty's third episode proved to be the most explosive yet. AC-12's investigation threw out plenty of twists and turns and the tension is seriously hotting up surrounding Operation Lighthouse and the potential suspects.
The episode, which aired on Sunday, saw Detective Superintendent Ian Buckells arrested for his actions surrounding the murder investigation into Gail Vella – but it seems that many have an intriguing new theory about the officer and his involvement in the operation.
WATCH: Line of Duty episode three - what you might have missed
Taking to Twitter, many voiced the idea that Buckells (played by Nigel Boyle) is in fact working for AC-12 and Superintendent Ted Hastings after spotting a connection between the two.
One person wrote: "I have a #LineOfDuty theory... Buckells is an undercover AC-12 agent known only to Hastings. Recruited through Masonic connection and instructed to get close to Ryan to find H."
Another said: "Still thinking about that throwaway remark about Buckells being at his 'Masonic lodge', implying a link with Hastings... #LineOfDuty." A third echoed this and also tweeted: "Couple of rogue #LineOfDuty predictions: Jo Davidson is Ted's daughter. Buckles is undercover AC-12 looking into Kate as being one of the H's."
Many fans think Buckells could be undercover...
Meanwhile, despite other fans being unsure of his undercover collusion with Ted, many are convinced that, either way, Buckells isn't the mystery 'fourth man' and is in fact being framed. A fourth said: "Buckells being set up, he couldn't run a bath let alone an OCG!! #LineOfDuty," while another wrote: "Buckells and these golf references! I feel like it's a red herring #LineOfDuty."
Elsewhere in episode three, original OCG member-turned-copper Ryan Pilkington orchestrated a shocking car crash into a lake which subsequently killed a fellow officer, all the while attempting murder against key witness Terry Boyle. However, the unsuccessful attempt on Terry's life didn't go unnoticed by DI Kate Fleming – who witnessed the crash and exposed his true identity to DI Steve Arnott.
Meanwhile, Steve found himself in hot water after Steph Corbett informed Hastings about his prescription pills usage, which prompted routine drug testing and put his job in jeopardy.
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