Her foster father, Siôn Jenkins, was originally convicted for the crime, but after two retrials in which the jury was unable to reach a verdict he was formally acquitted.

Billie-Jo's family have always maintained that Siôn Jenkins is guilty, and blamed the outcome of the final trial on the fact that the judge ruled inadmissible new forensic evidence due to it being introduced too late for the defence team to respond.

[3][4][5][6] The forensic examination also found that the bloodspots contained tiny fragments of metal from the murder weapon, an iron tent peg.

[9][12] Two schoolfriends of Billie-Jo said that she had confided in them that Siôn had punched her and scratched her neck, and that on one occasion she had come to school with blood on her face, saying that Jenkins had held her up against a door after she had told him to stop slapping her pet dog.

[12] The schoolfriends also reported that on multiple occasions she would come to school with bruises on her arms and legs, claiming they were from arguments with her father.

[12] Jenkins would later admit slapping Billie-Jo in anger, and then revealed that he occasionally hit the children with a slipper or with a ruler.

[14] Siôn Jenkins worked as the deputy headteacher of local boys' comprehensive William Parker School in Hastings.

"[15][18] After arriving home from a trip the next day Siôn said he asked Billie-Jo to turn down her music and evidence later indicated he had been infuriated when she had refused.

[20] Police asked her foster father Siôn Jenkins to make a public appeal, although shortly after this he came under suspicion, including from his wife,[22] and became the main suspect.

A police investigation revealed erratic behaviour by him around the time of the incident and the discovery of 158 microscopic spots of Billie-Jo's blood, found on his clothing.

[9] Billie-Jo had stayed at home to paint the patio doors in the rear garden, in order to earn extra pocket money.

[9] Police say that he did this to provide himself with an alibi, supported by the fact that he inexplicably drove around the nearby park in a circle and had taken an unusual route which extended the journey time.

[9] Police said that the idea that a stranger broke into the garden, found a weapon and killed Billie-Jo during the same 10 minutes Jenkins was away, apparently escaping without anyone noticing, was implausible.

[7] At his trial in 1998, the prosecution revealed that 158 bloodstains were found on the shoes, trousers and jacket of Siôn, and stated that this was impact spatter resulting from the assault on Billie-Jo.

[32] However, one paediatrician called the defence "impossible"[35] and the pathologist concluded that her injuries would have been so severe that she would not have been physically able to take the breaths to be able to do this and described the experiments as "wholly unrealistic".

[32]Jenkins claimed at trial that Billie-Jo could be disobedient and "impatient", stating: "She would simply destroy items of clothing or hurt herself, ripping the heads off dolls... if she was asked to do something she might not do it.

"[34] The court also heard of the lies Jenkins had conceived on his CV at trial, and it was said that he was under "considerable stress" at the time, since he would have been dismissed if his qualifications were found to be fabricated.

[17] The detective superintendent in charge of the case, Jeremy Paine, said that the murder was "a brutal act carried out in a moment of incomprehensible rage and violence".

[40] After he had been convicted of the murder, the judge revealed that Jenkins had also been charged with "obtaining pecuniary advantage by deception", relating to the lies he had conceived about his qualifications when applying for his job.

[42] The appeal court regarded this alternative explanation as making the conviction unsafe, stating it may have affected the decision of the jury had it been discussed at the first trial.

[42] At the retrial in 2005, forensic scientists stated that the microscopic blood spray could conceivably have been released from Billie Jo's injured airway as Jenkins moved her.

[20] It was also noted that Jenkins could have been in a flirtatious, sexualised relationship with his foster daughter at the time, and that evidence from his other children suggested that he "preferred" Billie-Jo to them.

[43] The second retrial was likewise unable to reach a majority verdict after three months of evidence, and at the Old Bailey in London on 9 February 2006, Siôn Jenkins was declared in consequence to be acquitted.

[44] Jenkins' acquittal was controversial, as it then emerged that the jury had not heard evidence from his wife at the time, who described him as a violent man who had beaten the children with a stick and had previously injured her.

[3][4][5][8] The scientific evidence, conducted by scientists from the University of Cambridge, also found that the bloodstains contained tiny fragments of metal from the tent peg which had been used to beat her.

[4] Jenkins said that he and his wife Lois were "so worried about prowlers and break-ins in the area where they lived that they had security lights and window locks fitted to their home".

[46] Jenkins' defence team had already been aware of the 'evidence' regarding this alleged suspect at trial, but had not raised it due to "tactical considerations".

[7] Siôn said Billie-Jo was alive and well before he set off on his 10-minute trip to the DIY store with his two other daughters, and she was found dead as soon as he came back.

[9] This meant that any third-party murderer would have had to have broken into the garden, found a weapon and killed Billie-Jo during the same 10 minutes Jenkins was away, and then escaped without anyone noticing.

[49] In a February 2022 Channel 5 documentary on the case, members of the police investigative team stated that Jenkins continued to lie in a book he wrote on the murder after his acquittal.