Image copyright Metropolitan Police

When Kyzer Gayle died in 2005 he was little over a year old. But it would be 10 years before the authorities knew about his death and longer still before they discovered what had happened to the boy from north London.

When asked about the whereabouts of her son, Victoria Gayle, 32, told different tales to different people. Friends and family heard that the boy - Kyzer Gayle - was with his dad. A London man who believed himself to be the child's father thought Gayle had custody. Some official agencies were informed that Kyzer had been fathered by a traveller who took him away at a young age. But the stories were false.

Kyzer died in 2005 when he was 13-15 months old and his mother hid the fact for more than a decade. Despite asking Gayle questions, no-one had tested the truth of her replies by establishing where her son really was.

A police investigation was triggered only by the accidental death of Gayle's two-year-old daughter, Ava, in 2015. Medical treatment was sought when Ava became ill, but her condition deteriorated and she died. A subsequent inquest - recording a verdict of accident - determined that she had swallowed a tiny battery, causing fatal internal injuries.

Image copyright Getty Images Image caption Kyzer Gayle was born in Northwick Park Hospital in February 2004

Following the tragedy, local investigators in Barnet, north London reviewed what was known about Kyzer. Finding themselves unable to account for the child, the case was referred to Scotland Yard. Beyond 2004, the year of his birth, there appeared to be no record of Kyzer being seen by anyone in authority. No attendance at school. No GP visits. No registrations with public bodies.

Inquiries revealed that some people who had met Kyzer as an infant were under the impression that he lived with his father in north London. Police traced the man, but he had not seen Kyzer for more than a decade. He said that following a brief relationship with Gayle in 2003, she later made contact to say he had fathered a son called Kyzer.

He told detectives he then had occasional contact with the child until, on one occasion when Gayle brought Kyzer to his home, she left and did not return. The man said he cared for the child for about five months until Gayle suddenly reappeared and demanded Kyzer back, which he felt he had to accept. He never saw the boy again.

Other witnesses described seeing a baby fitting Kyzer's description at Gayle's north London flat. These are thought to be among the last sightings of the boy.

Gayle has been described as a hoarder and the child was said to have been seen in a buggy in a junk-filled room.

Image caption Pen Mehmet, Victoria Gayle's former neighbour, reported her concerns to the authorities

Pen Mehmet, a former neighbour, told the BBC that Gayle was a "compulsive liar" whose flat was so packed with rubbish that "I couldn't tell you where her kitchen was".

She said Gayle had claimed in recent years that Kyzer "lives with his dad" and "that was the best way because that's how the dad wanted it". Ms Mehmet says she became so troubled by elements of Gayle's behaviour that she reported her concerns to the authorities.

During contact with Gayle, some official agencies did ask about her son's whereabouts. She told them the boy's father was a member of the traveller community and had taken responsibility for Kyzer at a young age. The claim appears to have been accepted and no-one ever sought out the boy.

Image copyright Metropolitan Police Image caption A photograph of the shed where the baby was found, taken after the police had removed the body

When Gayle was later evicted from her home, she stored some of her possessions in the garden shed of her mother and step-father who lived nearby, which was where detectives eventually found Kyzer's remains.

Lead investigator Det Ch Insp Noel McHugh told the BBC: "Within the shed we found a box. Within the box was what can best be described as a cocoon of gaffer tape, which concealed a cut-down buggy and in there was the clothed skeletal remains of the child we believe to be Kyzer." A bandage had been applied to the entire length of one leg. Gayle's mother and step-father denied knowing what had been stored on their property.

Before the discovery, Gayle had repeated to detectives the story about Kyzer's traveller father taking him away. Once his remains had been found, she admitted the story was untrue. But she denied harming Kyzer and claimed she had simply found him dead in his cot one morning - to which her reaction had been shock followed by denial. She said that recent internet searches for sulphuric acid had nothing to do with attempts to cover up the death.

Gayle said that, until the eviction, Kyzer's body had been kept in her home and she had covered up what happened because she was afraid of being judged and blamed for it. The passage of time means that experts have been unable to establish a cause of death, although there was evidence of malnutrition and arrested growth. Tests showed the north London man who looked after Kyzer for several months was actually not his father, although detectives eventually identified someone who was.

Image caption Victoria Gayle outside Kingston Crown Court in December last year

At Kingston Crown Court last December, Victoria Gayle pleaded guilty to preventing Kyzer's lawful burial. She denied charges of perjury and perverting the course of justice, which have been left to lie on file. She has been sentenced to 21 months in prison with the judge criticising Gayle's "web of lies" and saying the the full truth of her son's "sad and short life" will never be known.

A serious case review is investigating potential failings by Barnet Council and other official bodies. In a statement, the council said: "The death of any child is tragic and we are working with Barnet Safeguarding Children's Board to provide information for their serious case review and to establish any learning from our involvement with the family."

The Independent Police Complaints Commission (IPCC) has also opened an inquiry - currently on hold pending the serious case review - into potential police deficiencies. An IPCC spokesperson said it was "a complex case spanning more than a decade, and we now know the family of the child had significant contact, not just with the police, but also with other agencies".

Image caption Noel McHugh led the investigation that discovered the child's remains

Detectives are still making inquiries and Det Ch Insp McHugh told the BBC he was appealing for people to come forward who knew Gayle around 2004, when Kyzer was born. Police are also particularly interested in the period between 2007 and 2013, and are asking Gayle's former partners if she had any pregnancies or births police do not know about.

Jon Brown, from children's charity the NSPCC, says he finds it "deeply disturbing" that a child can "go missing for a decade". He told the BBC there were "a number of significant and important questions that are going to need to be addressed by the serious case review and by the IPCC investigation".

Pen Mehmet, Gayle's former neighbour, agrees and says she is angry and bewildered that Kyzer's death could go unnoticed for so long. "I think it's absolutely disgusting because this child's been missing and nobody knew.

"How can nobody know? I don't understand, how can nobody know?"