A couple said to have swapped the identity of their dead baby daughter to her twin sister in a bid to cover injuries they inflicted have been jailed for five years.
The seven-month-old was rushed to hospital in Blackburn, Lancs, after her parents reported she had breathing difficulties, and was pronounced dead shortly after.
Preston Crown Court heard Mohammed Karolia, 29, and wife Nafisa, 22, made a deliberate attempt to hide the ailing twin from the outside world in the weeks leading up to her death in June 2009.
It was alleged the defendants told medics at Royal Blackburn Hospital the girl was the healthier and smaller of their identical twins before they allegedly later switched to naming her sibling on the death certificate.
The couple denied any baby swap, which was described by their legal teams as "fanciful" and "far-fetched", but the jury convicted them in July of child cruelty after a five-week trial.
Both chose not to give evidence, they maintain their innocence and do not believe the other was responsible for the injuries, but the trial heard that no one else looked after the children.
Sentencing, Mr Justice Irwin said it remained unclear whether a swap did take place but what mattered was that the child had been hurt and "victimised" while the other identical twin was "looked after well".
Addressing the pair, he said: "Only you two know if both of you or one of you have directed and inflicted the injuries.
"Whichever of those is true, you certainly knew it was happening, you knew it was wrong, gave it encouragement and concealed it, and you have continued to deny it."
The Karolias will be released on licence halfway through their jail terms and will then have to serve an extended licence period of five years.
In opening the case, Joe Boyd, prosecuting, said the identity swap was uncovered by discrepancies in the head, weight and height measurements previously taken from the twins - known as Twin M and Twin A for legal reasons.
Members of the jury were told they did not necessarily have to believe the twin swap theory to return guilty verdicts.
Twin M had suffered numerous injuries including fractures to the ribs, legs and arms, and skull damage affecting the brain and central nervous system, the prosecution said.
She also had a mouth ulcer, unexplained scratching to the ears, bleeding in the eyes and injuries to the nose. The victim's nasal injuries were particularly "unusual" with damaged tissue suggesting her nose had been pinched with equal force on both sides by a clasp or clip.
The broken bones were said to have taken place between 24 hours and six weeks before death, while a post-mortem examination found she died of bronchopneumonia.
Mr Boyd said the Crown did not seek to prove any maltreatment by the parents caused the baby's death but said they had never provided a plausible explanation for the injuries.
The victim had only ever been out of their care for a matter of a few hours in her short life.
He said theoretically the injuries sustained could have been accidental but the number, the timescale and the lack of explanation for them "leads inexplicably to the conclusion they were inflicted deliberately by one or both of the parents".
Explaining the alleged twin swap, Mr Boyd said: "The living twin's progress is consistent with that of Girl A, while the dead twin's progress corresponds to Girl M.
"Growth charts for both twins make it clear that the parents have at some stage swapped the babies. They have very probably done so to seek to conceal the mounting injuries being suffered by the child who died - always the bigger twin but, for some reason, rejected and abused by them."
Mr Boyd said the couple had tricked a number of visiting health professionals into thinking they were seeing Twin M.
He added that neighbours had only ever seen the Karolias with one baby and there was nothing to indicate they had twins.
The defendants, of Meadow Close, Blackburn, had each denied the offences which took place between November 26 2008 and June 16 2009.
The judge said Nafisa Karolia - who had been taken into care herself as a teenager from an abused background - was the mother of three children and pregnant with her fourth child at the time of the cruelty.
"You bore the overwhelming share of work of looking after these children," he told her.
"However, the facts do not sustain the picture of an overburdened woman hurting or neglecting a child because she is at the end of her tether. All of your three other children were looked after well.
"The surviving twin has never suffered any injury or neglect and she appeared to have been very well cared for.
"What emerges from the evidence is repeated cruelty to one child and victimisation of another."
The judge said the injuries to the twin's nose were particularly "unpleasant" and "upsetting" and would have been "extremely painful".
Both defendants had undergone psychiatric reports and none had an underlying condition which would explain their actions.
Their barristers successfully argued that neither should be dealt with by way of an indeterminate sentence for public protection, under which they would have had to satisfy a parole board they did not pose a significant risk of harm to others before being released.
Suzanne Goddard QC, representing Nafisa Karolia, said all her three surviving children had been taken from her and she was unlikely to have any extended contact ever again.
She came from a traditional Asian family of seven and had in her teenage years been ill treated by her mother and elderly brother, the court heard.
She was taken into foster care aged 14 and had gone to enter education and meet her husband who "she loves deeply" and "does not to seek to blame in any way" for the injuries to their daughter.
Graham Wood QC, defending Mohammed Karolia, said: "He firmly believes that what happened with the loss of baby was God's punishment for his lack of commitment to Islam.
"His attitude remains the same. There is a continuing denial of culpability.
"He is a man who has otherwise been dutiful and loving, and dedicated to his family - supported by his immediate family network.
"This was not a loveless or arranged marriage. He has now lost everything."
Detective Inspector Pete Broome: "I don't think any period of imprisonment would adequately sum up the gravity of this case.
"In a now very lengthy career I don't think I've dealt with one more serious. This had got to be up there with the very worst.
"They had come up with an elaborate plan. Quite why they did what they did only those two will ever know. Sadly, the child can no longer speak for herself because she's no longer here.
"I wish I knew why they deliberately targeted one child. I've been asking myself that question for two years.
"In my opinion, I think they did try to swap the identity of the babies. All the evidence which came out clearly unequivocally shows the baby who sadly died was not the one the parent had claimed. It was done to cover up the abuse of the child that died.
"I don't think anything more could have been done. The family weren't known to the police."
Gladys Rhodes, Blackburn with Darwen Council's strategic director of families, health and wellbeing, said: "The death of any child is tragic and this case was particularly harrowing due to the severity of the concealed abuse that this helpless baby was subjected to.
"We welcome these sentences and the closure to this case. We would like to make it clear that we had no previous involvement with any of the children in the family, but the child's siblings are now in the concil's care and care proceedings are ongoing."