These are the dramatic scenes from a new TV adaptation that recreate the chilling moment Hazel Stewart and Colin Howell murdered their unsuspecting spouses.
The striking images from The Secret reveal the actors playing murder victims Lesley Howell and Trevor Buchanan lying lifeless on the floor after they have been gassed.
The first part of the much-anticipated drama will be aired on Friday evening.
It is the story of real-life God-fearing adulterous couple, Coleraine dentist Colin Howell, played by Jimmy Nesbitt, and Sunday school teacher Hazel Stewart, played by Genevieve O'Reilly. They murdered their partners in May 1991 so they could be together.
Images from the ITV drama show Nesbitt and O'Reilly as Howell and Stewart, who then went under the married name Buchanan, in the hallway of her Coleraine home holding the murder weapon - a specially adapted hosepipe that was used to gas their victims while they slept.
One image shows Howell's wife Lesley lying on the sofa in their family home where she had fallen asleep before she was murdered.
Another image shows Trevor's lifeless body lying in the hallway of his marital home with a deranged looking Howell bending over him.
Howell later put the bodies of his victims in the boot of his car before abandoning them in a garage in Castlerock to make it look like a suicide.
Howell and Stewart's terrible secret was not discovered until almost 20 years later, when he finally confessed to murder.
He walked into a police station and told officers that he and Stewart had been having an affair at the time of the murders and had planned them together.
Howell is currently serving a life sentence in Maghaberry Prison.
Stewart pleaded her innocence but was found guilty of murder. She is serving a life sentence in the women's prison at Hydebank.
The extraordinary story of Howell and Stewart, (below) continues to both shock and fascinate.
Nesbitt, a north coast native himself, has said he had been fascinated by the story for some time and that he had been very keen to play the character of Howell.
"Obviously, what drew me to it was that it happened in my home town, added Nesbitt. "It's an incredible story which lifted Northern Ireland out of the torture of the Troubles - out of the frying pan into the fire.
"He (Howell) was a great character, and I was desperate to do it (play the role)."
The Secret was written by Bafta-winner Stuart Urban and directed by Nick Murphy.
It will be screened on ITV on Friday at 9pm.