Everybody thought they had spotted the twist in Line of Duty series 4 episode 2

Line of Duty series 4 took another devious twist – but not quite in the way we were expecting.

• Meet the cast of Line of Duty series four
• Who is Line of Duty series four star Thandie Newton?
• The real AC-12: discover the police anti-corruption officers who inspired Line of Duty

In episode two of Line of Duty, DCI Roz Huntley overhears a forensics officer bagging up a key piece of evidence, writing out the reference number KRG-13.

The only thing is, Huntley thought she heard KRG-30, as we saw her write the number down on her hand to remember.

She later attempted to tamper with the evidence in order to conceal her involvement in the murder of Tim Ifield – but viewers had spotted the slip-up.

https://twitter.com/Tombo_h/status/848635006092288000
https://twitter.com/bjstevec/status/848655698703601664
https://twitter.com/Sara_Brown21/status/848636469027774465
https://twitter.com/LeslieMilnes/status/848635552182259712
https://twitter.com/PaddyMagrane/status/848635512822915073

Even the series' star Thandie Newton was shouting at the screen watching back home...

https://twitter.com/thandienewton/status/848634923397390336

However, just when we thought we knew how this was going to end, Line of Duty caught us off guard again. Huntley spotted her error when she switched the evidence bags with the vital blood samples, and hastily scribbled a correction.

It was enough to put both the murder investigation and AC-12 off the scent – but for how long?

Viewers think this last-minute switcheroo still might come back to haunt her.

https://twitter.com/prettyboots/status/848666705245200384
https://twitter.com/doktorb/status/848636127246417921
https://twitter.com/Daliso_AFC/status/848661822303547393

Even if not everyone's entirely sure the little fridge scene is ENTIRELY accurate...

https://twitter.com/HennieInglis/status/848724042181996545