This is the chilling moment one of Margaret Fleming's Murderers, Edward Cairney, smirked the police asked him if he had killed her.
The 77-year-old was today found guilty of murdering the victim with April Jones, 59, around 1999.
The callous will be sentenced next month.
Footage released by the Crown Office today shows the evil carer again and again answer "no comment" when asked questioned by a detective.
A smug Cairney can be seen sitting with his army crossed, refusing to co-operate with the questioning – before fidgeting with a handkerchief during the four-minute clip.
At certain points he raises his voice towards the detective to emphasize his "no comment" position.
The officer asks Cairney: "Is Margaret Fleming dead?", "Eddie, are you involved in her disappearance or murder?" and "Did you murder Margaret Fleming?".
To each of the questions, Cairney simply replied "no comment" with a smirk on his face.
Picking up on the facial expression, the detective said: "I do not know if it's a critical thing, but a crucial issue and you're smirking."
Cairney then hits out, asking "How is it a crucial question?"
"Did I murder her? Is that what you're saying? No comment," he added.
He added: "Maybe I'm smirking at your manufactured sincerity."
Cairney "practically no sincerity", to which the answer: "I know what you are."
Earlier, senior cop Detective Superintendent Paul Livingstone spoke out against Cairney and Jones who "kept Margaret prisoner within their home."
He said that Margaret was "subjected to daily punishment which included being tied up, having her hair cut short and deprived of food.
"The treatment which has been reported to be as horrific and the conditions in which it has been utterly disgusting and uninhabitable.
"Margaret was a very vulnerable young woman who was manipulated, abused, neglected and ultimately murdered by the two people who should have been looking after her."
He added: "We will never know just how Margaret was killed.
"She must have felt that she was alone in the world with her heart.
"Margaret was just a young woman when she was murdered." "Who knows what she was?"
Margaret Fleming, who had learned difficulties, vanished "from the face of the earth" around December 1999. Her body has never been found.
Jurors found the couple murdered her by unknown means between December 18, 1999 and January 5, 2000 at their home in Inverkip, Inverclyde, or elsewhere in Scotland, and then tried to cover up the crime for almost 18 years.
Police launched an investigation after it became apparent in October 2016 that Margaret was missing.
Social Routine Services inquiries were said to have sparked concern over her whereabouts.
The case attracted major police resources and significant media attention as it was claimed the last independent sighting of a family event on December 17, 1999.
As the inquiry progressed, it came back something "sinister" had happened.
Specialist search teams for the cottage where she lived and excavated the grounds looking for clues to help track her down.
Her carers were arrested in October 2017.