A mother and her civil partner have been jailed for life for murdering her toddler son after subjecting him to more than two years of abuse and neglect.
Defenceless two-year-old Liam Fee died at his home near Glenrothes, Fife, on March 22, 2014 after suffering heart injuries similar to those found on road crash victims.
His mother Rachel Trelfa or Fee, 31, and her partner Nyomi Fee, 29, tried to pin the blame for the death on a young boy but were convicted of Liam's murder in May following a seven-week trial at the High Court in Livingston.
The pair - originally from Ryton, Tyne and Wear - were also found guilty of a catalogue of horrific cruelty against two boys in their care, including the one they blamed for Liam's death.
Sitting at the High Court in Edinburgh, judge Lord Burns handed both women mandatory life sentences.
He ordered Trelfa to serve a minimum of 23-and-a-half years behind bars, while Fee must spend at least 24 years in prison before she can even be considered for release.
The pair displayed little emotion as their sentences were delivered, one after the other.
There was silence in the packed courtroom as the pair were led away to the cells.
Liam's father Joseph Johnson looked straight ahead as the women were told the punishment parts of their life sentences.
Lord Burns told the couple they had subjected the children to "a cruel and pitiless regime of ill treatment and neglect".
"In the case of Liam, that treatment included the assault which caused his death," the judge said.
He added that the post-mortem examination showed the two-year-old had been "subjected to a prolonged course of violent behaviour".
The case of "unyielding, heartless cruelty" was one of the most distressing ever heard in a Scottish courtroom, with some evidence reducing jury members to tears.
Liam had suffered a severe blunt force trauma from a blow or blows to his chest and abdomen and had more than 30 external injuries on his lifeless body.
Jurors heard there had been an escalation of violence towards the blonde-haired, blue-eyed boy leading up to his death, which included the couple failing to get help for the toddler when they knew he had a broken leg and fractured arm.
Their "callous indifference" to his injuries would have left the child in agony, but the killers refused to get him medical aid, choosing instead to search the internet on their phones under terms such as "how do you die of a broken hip", "how long can you live with a broken bone?", and "can wives be in prison together?".
Under oath, the women admitted serious failings over the lack of medical help sought for Liam and put it down to fears the child would be taken into care.
But they denied murder and, as part of their web of lies, tried to shift the blame for the killing on to a boy of only primary school age, who they claimed had been acting in a sexualised way towards Liam.
The boy was so scared of the women he initially told police and social workers that he had "strangled" the toddler - but suffocation was not the cause of death.
The evidence pointed to a significant delay between the discovery by the women that Liam was dead and the emergency services being contacted by a seemingly hysterical Fee shortly before 8pm on the night in question.
The "panicking" pair used the time instead to dismantle a makeshift cage they had built to imprison the youngster they falsely accused of killing Liam.
The couple - who had no previous convictions - were found guilty of all eight charges against them, with a majority verdict returned on the murder charge.
They were convicted of assaulting Liam over more than two years prior to his death and of ill-treating and neglecting him from January 2012 onwards.
The jury also convicted them of horrific abuses against two boys, who cannot be named because of their age.
These included denying the youngsters access to the toilet then forcing them to take cold showers when they wet the bed; imprisoning one in a home-made cage; and tying another naked to a chair in a dark room where snakes and rats were kept after telling him that a boa constrictor ate naughty boys.
Harrowing evidence given by the boys in a series of lengthy video interviews was crucial to securing the convictions.
The trial heard that a number of people had expressed concern about Liam's wellbeing during his short life. Fife Council is now reviewing how it handled the case.