Muti factbox

Most common in KwaZulu-Natal, Northern Province and Swaziland Practitioners either sangomas, who diagnose, and inyangas, who prescribe potions Human sacrifice rare - herbal or animal ingredients usually used Muti sacrifice blamed for at least one South African death a month

One of the most disturbing aspects was the likelihood that Adam was likely to have been beheaded while still alive.

"This is because the screams of the victim are believed to strengthen the power of the muti," said Professor Hendrik Scholtz, an expert in witchcraft murders at the University of Witwatersrand in Johannesburg.

For Commander Andy Baker and Detective Inspector Will O'Reilly - the two Scotland Yard officers who persuaded former South African President Nelson Mandela to make an appeal for help in identifying the boy - it has become a personal crusade.

Mr O'Reilly said: "This case is unprecedented. There is no similar case - of a child of this age ever having been dismembered - since police records began 40 years ago."

The body, dressed only in a pair of red shorts, was spotted as it floated past Tower Bridge on 21 September last year.

Red herring

A few days later a number of black candles wrapped in a white sheet, which had a Nigerian name written on it, was washed up nearby and police assumed there was a connection.

But it later transpired that the sheet and candles was part of an innocent prayer service carried out by a Nigerian family concerned about one of their relatives who was in New York in the wake of 11 September.

Dr Hendrik Scholtz carried out a second post-mortem

The boy was aged between four and seven and had been circumcised, which led police to believe he was more likely to be from West Africa or Central Africa rather than Southern Africa.

Cutting-edge science has been brought to bear on the case.

Adam's DNA was taken in an attempt to find out if he was one of thousands of children who go missing every year.

Last month scientists began "bone mapping" tests on his body in an attempt to pinpoint the country and region where he lived and grew up.

A pathologist discovered traces of pollen in the stomach which led detectives to conclude the child had lived in Africa until shortly before his death.

Special conference

Traces of cough linctus were also found in his system, which suggested he had been well cared for in the weeks before his murder.

In January, at Bramshill Police College in Hampshire, Mr Baker and Mr O'Reilly addressed a conference of detectives from all over Britain on the case.

Television news cameras were on hand to film the seminar but some of the slides shown to the detectives were too graphic for public consumption.

The shorts had German washing instructions

Prof Scholtz spoke in clinical detail as he pointed out the marks on the stumps of the child's neck, arms and legs.

The detectives working on the case were well aware from an early date that they desperately needed publicity to crack the case because they could only find the killers if they knew the identity of the victim.

Seven months on they still do not know the name of the boy - who was given the name Adam by detectives - hence the appeal by Mr Mandela, a figure respected across Africa.

Huge resources have been thrown at the case.

Interpol have been involved and police in 63 countries have been contacted. There has been considerable co-operation with forces in Germany and Holland.

Dutch link examined

Police in the Netherlands were looking into a similar case, involving a young black girl.

Earlier this month BBC Two aired a documentary called Nobody's Child which centred on the case of Adam and linked it to muti practices in South Africa.

The programme's producer, Fatima Salaria, told BBC News Online several facts suggested muti was involved in Adam's death.

"Red and orange are powerful colours in muti, so it is significant that he was wearing red shorts. It is also significant that he was found in running water," she said.

His genitals were intact which suggests the motive was not connected to fertility.

But the absence of his head and hands was significant.

Ms Salaria said: "There have been cases where people are killed and their brains eaten, so that those taking part can get into university.

"Hands are sometimes cut off and placed underground at the front of shops to encourage more customers."

Anyone with information about the Thames killing is asked to call the police incident room on 0208 853 1212.