**Article contains spoilers**
Known for her cold attitude, and ruthless interrogation skills, DCS Patricia Carmichael is beginning to become some viewers' prime suspect for the mysterious ‘H’.
Anna Maxwell Martin’s character made a comeback for season six, announcing cuts and a restructure of AC-12.
One eagle-eyed Line of Duty fan took it a step further and spotted a clue on Martin's social media account that could reveal a lot more about Carmichael ahead of the season finale on Sunday (2 May)
Who is DCS Patricia Carmichael?
DCS Carmichael was introduced to Line of Duty viewers in the fifth season of the hit show, as she stepped in to investigate proceedings at AC-12.
Introduced specifically to interrogate Superintendent Ted Hastings over his alleged links to the Organised Crime Gang, the character quickly became iconic for her snarky and quietly ruthless interrogation skills.
DCS Carmichael is in charge of Anti-Corruption Unit 4. Viewers were not presented with a lot of information about the character, but were treated to an insight into what Superintendent Hastings thinks of her.
Carmichael returned in episode five of season six. Her return came as Hastings looks to be forced to retire, and major cuts are set to take place inthe anti-corruption units.
What did Anna Maxwell Martin post on Instagram?
Fans began to speculate whether Patricia Carmichael was also corrupt, following some shady moments in episode six of season six.
During the interview between Carmichael, Steve Arnott, Hastings, and Jo Davidson, she kept interrupting when the topic drifted towards high level corruption within the police force.
Anna Maxwell Martin added another layer of suspicion on to her character DS Carmichael after a post on her Instagram account.
Throughout Line of Duty one huge clue has remained constant - ‘H’ has the inability to spell definitely, instead writing ‘definately’.
On Instagram, the actor posted a picture of her dog with the caption ‘Definately mama to this bank drain’.
The spelling mistake led fans to instantly pose the question of whether this was a cryptic clue from Martin regarding her character’s possible links to organised crime.
Carmichael’s morse code with her pen
Patricia Carmichael got fans speculating about her relationship with the OCG again during episode 6.
After the interview with Davidson, some viewers believe they found a secret hidden message connecting Carmichael to ‘H’...all by the click of her pen.
During the chat, Carmichael was seen tapping her pen four times on the table - which has led to some fans speculating she was actually using morse code.
One viewer noted on Twitter: “Whilst interviewing Davidson, Carmichael taps her pen on the table 4 F*****G TIMES!! We all remember Dots message when dying, 4 Dots .... 4 taps in Morse code? F*****G H!!!"