Police officers investigating the murder and dismemberment of a child whose body was dumped in the River Thames say a ritual killing is now their 'major line of investigation'.
Their comments follow a second post mortem examination conducted on the child's remains by South African pathologist Dr Hendrik Scholtz.
Dr Scholtz was called in because of his expertise in ritual killings of a kind often seen in southern Africa.
Police are looking at whether the UK has seen its first "muti" murder - killings associated with African witch doctors who use body parts for medicines.
Detectives believe the dismembered body could be the first such victim in Britain.
The comments were made at a conference on ritual killings held at the National Police Training College at Bramshill, Hampshire,
The conference heard from Dr Scholtz, who said: "There was an examination of detailed photographs from the initial post mortem investigation, exhibits and specimens including tool marks on the bones of the limbs and neck of the deceased.
"It is my opinion that the nature of the discovery of the body, features of the external examination including the nature of the wounds, clothing and mechanism of death are consistent with those of a ritual homicide as practised in Africa."
He said that the fingers, brain and skull of the victims were used as potions and medicines for those who wanted to awaken the supernatural forces.
But he added the incidence of ritual murder in southern Africa had been falling over the last few years, largely because of political changes in the area.
Dr Scholtz explained that he thought the boy was probably nearer to the age of seven than to four.
He added that the circumcision of the victim had some relevance to finding the origin of the ritual because in South Africa boys were not normally circumcised until they are 18.
Police have released a graphic depicting the boy in the orange shorts he was wearing when the body was found.
They said the possibility of ritual murder would now be their major, but not only, line of investigation.
The youngster's torso was spotted floating in the Thames by a man walking across Tower Bridge on September 21 last year. It had been in the water for up to 10 days.
Police found seven half-burned candles wrapped in a white sheet washed up on the southern shore of the Thames in London.
A name - Adekoye Jo Fola Adeoye - was written on the sheet and the name Fola Adeoye was inscribed on the candles.
Forensic experts estimate that the boy, who was of Afro-Caribbean origin, was aged between five and six and detectives have named him "Adam".
A reward of £50,000 has been offered for information leading to the conviction of his killer.
Police have appealed for information from anyone who can help identify the child, who can help with the name written on the sheet or candles, or who say anything suspicious on the Thames foreshore.
Police have also been liaising closely with detectives in Germany and Belgium where three similar cases have emerged, involving the murder of children whose bodies were disposed of in running water.