BBCAs they walked through arrivals at Manchester Airport, a couple seemed to be behaving oddly towards their baby.
Something did not sit right with Border Force officers. One worried the relationship between the three was "not genuine".
Officers pulled the couple for questioning. The man, Raphael Ossai, claimed to be the girl's father.
He handed them a birth certificate for the baby, which showed his travelling companion, Oluwakemi Olasanoye, as the child's mother.
But officers found a second birth certificate, hidden in the lining of the couple's luggage. It named another woman, Raphael's British wife, as the little girl's mother.
It was the start of a mystery that remains unsolved - the little girl's true identity is still not fully known.
What we do know is the child is not related to any of the adults. The girl, who we are calling Lucy, seems to have been born in rural Nigeria in September 2022, and given to an orphanage when she was just three days old.
The couple who carried her to the UK, Ossai and Olasanoye, pleaded guilty to immigration offences and were sentenced to 18 months in prison followed by deportation.
Now Lucy has been in care in Manchester for nearly two years. The Nigerian High Commission did not engage in depth with the case despite multiple requests from the High Court.
For the last nine months the High Court in Manchester has been trying to find out who Lucy really is, as it decides what her future should be.
The court heard that on June 20 2023, Ossai and Olasanoye unlawfully brought Lucy to the UK from Lagos, via Addis Ababa. Olasanoye had a visa to work in the UK and agreed to travel with Ossai and Lucy.
When the couple were sentenced in criminal court, it was believed that Lucy was the child of Ossai and his Nigerian-born British wife.
Ossai met his British wife in Kenya and married her in Nigeria in 2017 – but he had never been to the UK. When he applied for a visitor's visa, he was turned down due to financial circumstances.
At the time of sentencing, the judge said the "principal motive for this offence" was to bring the baby to the UK so he and his British wife could live as a "family" with Lucy.
However during the High Court hearing, DNA tests proved Lucy is not related either of the adults.
Documents presented to the court said that she had been born to a young student in rural Nigeria, who was not able to care for her. Her father was not known.
The papers indicated the mother had voluntarily relinquished Lucy to an orphanage.
Ossai and his British wife said they had been looking for a little girl to adopt, and he collected Lucy when she was a tiny baby.
The couple had permission to foster the little girl but not to adopt her or take her out of Nigeria.
Ossai, a music producer, took Lucy to a small flat in Lagos where he looked after her for the next nine months.
He told the court he had cared for the baby well – that he had fed her properly, played her music, and kept her safe.
But a social worker from the Children and Family Court Advisory Service CAFCASS said she believed Lucy had been neglected, underfed and under stimulated.
She had met the little girl when she was just over a year old, in October 2023.
"It was really sad when I met her," a social worker told the court.
Giving evidence, she said it was as though the child did not realise "she was actually a person".
"She was so lost, and not really present… she just felt so alone yet she was surrounded by people," she added.
During an observation session, the social worker said Lucy became very "panicky" when her foster carer stood up to leave the room.
She also displayed an "extreme cry" that was "very difficult to soothe".
When asked whether Lucy could have been traumatised by the flight or by her transfer to care, the social worker said she believes it is unlikely that alone was to blame.
She added that if Lucy had developed a secure attachment to Ossai, that would have been transferred to her foster carer.
The judge said the child lacked "basic parental attachment" but did not make a finding on the cause.
"I am sure that her being brought into this country illegally and thus separated from her carers is bound to be a significant factor," he said.
Although Ossai has been sentenced to be deported, he and his British wife asked the High Court to assess them to care for Lucy.
Ossai said that he thought of Lucy as his daughter. His lawyers said that as the Nigerian authorities had approved him as her foster parent, the English court had no power to take her away.
Lucy had always been happy with him, Ossai said, and he thought taking her into care had upset her, especially placing her with white foster carers.
"The white may be strange to her," he added. "When they took her from me I saw the way she was looking at them."
His lawyers raised concerns that if Lucy were adopted by a white family, she would lose her cultural identity.
Ossai's British wife said Lucy "is like that precious gift that I desired so much".
She told the High Court she would do "anything and everything" for her, adding "I see her as my child".
Both broke down and cried in court when they talked about the little girl.
The High Court Judge hearing the case, Sir Jonathan Cohen, rejected Ossai and his British wife's application to be assessed to care for Lucy.
He said the lies they had told and the actions they had taken, especially moving Lucy from Nigeria, had "inevitably caused her very significant emotional harm".
Lucy has been placed with several different foster carers and is residing in at least her third new home since her arrival in the UK. In April, the judge ordered she be placed for adoption in the UK and that her name be changed.
He said that Lucy "needs to have the best opportunities going forward in the world", and that can "only be done in a placement in an alternative family".
The judge added that she would be provided with "background" about her heritage and told what happened in her past.
He found that Ossai and his British wife had a genuine desire to adopt Lucy.
Julian Bild, an immigration lawyer for anti-trafficking charity Atleu, said in circumstances where a woman is a UK national and a child is a UK national via adoption or otherwise, "it is likely the family would be allowed to stay here".
It is possible for a child to receive British citizenship if they are brought to and physically adopted in the UK, he said.
But he added that it is "very, very unlikely that a Nigerian could simply adopt a child to improve their immigration situation and get away with it because that would be pretty transparent".
"A person seeking to bring a child to the UK for the purpose of adoption would first need to get a Certificate of Eligibility from the UK government before being able to do so.
"The genuineness for all of this to happen is obviously looked at very closely by the family courts, social workers and experts to ensure the arrangement is in the best interests of the child."
The Home Office said it could not comment on individual cases and therefore could not clarify whether Ossai and Olasanoye had been removed from the UK.
A Home Office spokesperson said: "Foreign nationals who commit crime should be in no doubt that we will do everything to make sure they are not free to roam Britain's streets, including removing them from the UK at the earliest possible opportunity.
"Since the election we've removed 3,594 foreign criminals, a 16% increase on the same period 12 months prior."
The Nigerian High Commission did not respond to our requests for comment.
