With Line of Duty’s latest episode ending on a cliffhanger, there have been theories on who DCI Jo Davidson (Kelly Macdonald) might be related to.

Forensic officers had swiped the DCI’s fingerprints from her ex-lover Sergeant Farida Jatri’s home and it ended up closely matching someone whose DNA was already in the police database.

This means that the dodgy cop and the unknown individual are related to each other.

Steve Arnott (played by Martin Compston) and Chloe Bishop (played by Shalom Brune-Franklin) gave Ted Hastings (Adrian Dunbar) a folder with the individual’s information, which shocked him and left the audience trying to figure out who it may be.

Of course, fans don’t know who it is, but it won’t stop us from wondering...

Tommy Hunter

Tommy Hunter
Tommy joined the police force as an undercover OCG member

A lot of Twitter users have been solving the puzzle on who the unnamed person could be.

Many came to the conclusion that Tommy Hunter (Brian McCardle) - who was the first leader of the OCG (organised crime group) back in series one - was the missing link.

He later joined the police force as an undercover OCG member but was involved in an ambush in series two which put him in critical condition.

Tommy was later killed in hospital.

As Tommy was also Scottish, some think it may mean the two could be related.

Nigel Morton

Neil Morrissey
Nigel Morton could be returning

Many believe that Nigel Morton (played by Neil Morrissey) could be returning this season to wreak havoc.

Considering he was a close pal of corrupt officer Tony Gates (Lennie James) and had no issue spitting on his colleagues, it would be no shocking revelation if he had some sort of connection with Jo.

The actor recently spoke on This Morning on the possibility of him returning to the series.

He said on the talk show: “I keep telling Jed Mercurio, I’m very much alive. I just say, ‘Just bring me back and shoot me in the face’. That’s what he does to all the stars, doesn’t he?”

John Corbett

Stephen Graham
Some believe John and Jo were separated when they were young

Twitter detectives also have an inkling that DS John Corbett (Stephen Graham) might be related to Jo based on the framed photograph of Jo’s mother.

Some think that the woman in the photo is actually Anne-Marie McGillis, who happens to be John’s mother.

Anne-Marie was killed by the IRA in 1989 for being a police informant so John was sent to Liverpool to be raised by his aunt and uncle.

Could this mean that Jo was sent to other family members in Glasgow?

Danny Waldron

Daniel Mays
Danny grew up in care

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There is a small possibility that sergeant Danny Waldron (Daniel Mays) might be the unknown relative.

The armed response squad leader grew up in care, so there is a chance he never knew his birth family.

The Sands View boys home paedophile ring - of which Danny was a victim - was even discussed this season

Could Danny and Jo have been separated during their childhood and sent to different families?

Kate Fleming

Vicky McClure
Jo was accused of having an affair with Kate Fleming

It has already been speculated that DI Kate Fleming (Vicky McClure) will be playing an important role this season.

Farida had accused Jo of sleeping with her colleague, which she sarcastically denied.

However, her being Jo’s relative may throw a spanner into the works...

*Line Of Duty returns next Sunday at 9pm on BBC1