Liar creators have promised a "classic whodunnit" for the second series of the gripping drama, but fans will have to wait until 2019 to find out who killed evil Andrew Earlham.
The end of the finale saw the dead body of the serial rapist with his throat cut and floating in the water.
Co-writer Harry told The Mirror of the second series: “There are certainly a few suspects and we hope to explore that further.
"Andrew has been missing for several weeks and then we see his dead body in the empty marshlands.
"The question is: 'what happened in those missing weeks that led to Andrew’s demise?'"
The writing duo have already began work on the hotly anticipated sequel, revealing Ioan will appear in flashback sequences.
Jack said: "We don’t want to do it cynically – it will be a new set of lies and perceptions."
The pair also addressed concerns from frustrated fans that the ending offered no clue as to who was behind Andrew Earlham's fate.
Jack adds: "We’ve raised several more questions with this ending but for those who feel it’s a cruel cliffhanger that asks too many questions, fear not, it’s coming back for another series.”
Andrew Earlham- just as his victim Laura Nielson found the evidence to convict him - in the shocking final episode.
The dogged teacher (Joanne Froggatt) had talked her way into his elderly mum's home where she found his stash of video memory cards and his camcorder hidden away in his shed.
Luckily, Laura made it to the police station to share her evidence, with Detective Rory Maxwell assuring her the evidence would be enough to put Earlham away.
But having received a phone call from his mum's carer just as Laura was digging through his belongings, the surgeon had, it seemed, done a runner.
TV news reports at the end of the episode showed him "missing for three weeks" before the shot of his body came into view.