The boy known as Adam whose torso was found dumped in the river Thames was paralysed and killed by a poisonous bean used in African witchcraft.
Police believe Nigerian occultists used a calabar bean on the boy as part of a ritual killing in which his throat was slit. Minute traces of the bean have been found in his stomach by specialists at the Royal Botanical Gardens at Kew.
The discovery is the latest development in the murder inquiry after the discovery of a Nigerian boy's headless and limbless torso in the river near Tower Bridge in September 2001. Police are confident they will be able to bring charges despite their failure to identify the victim.
The Attorney General also took the unusual step yesterday of revealing that he may personally lead a prosecution in the case in a bid to deter the growing tide of child traffikers.
A statement from the office of Lord Goldsmith QC said: "The Attorney General has expressed an interest in leading for the prosecution in this case, not just for Adam's sake but - if he was a victim of trafficking - to send a clear message to those who deceive, coerce or force vulnerable people to leave their homes for a life of exploitation and misery - or worse - that they will not escape justice."
A people-smuggling gang based in Britain is thought to be directly involved in the murder, which may have been committed to bring the criminals good luck. Several people are believed to have been involved in the killing and an African witchdoctor may have been hired to cut up the body.
Identification of the rare calabar bean provides further evidence that the boy, who was aged between four and seven, was murdered as part of a black magic ceremony.
The calabar, or "ordeal" bean as it is known in west Africa, where it originates from, is traditionally used to test a suspected witch or criminal. If the person dies from eating the bean they are thought to have been rightly punished; if they survive they are considered innocent. The bean may have been used to subdue Adam up to 24 hours before his death.
A Metropolitan Police spokesman said: "The bean is often used for witchcraft purposes on the western coast of Africa. It can be fatal if consumed and is also known to cause paralysis."
A file is being prepared for the Crown Prosecution Service, raising the possibility of extraditing suspects from more than one country. Detectives have visited Nigeria and, by analysing the mineral content of the boy's bones, scientists have concluded he was brought up in a particular part of the country. They also discovered that the boy had been fed a potion of mixed bone, clay and gold.
Part of the contents of his stomachhave been sent to experts in New York who dealt with bone identification of people who died in the 11 September attacks.
Commander Andy Baker of the Metropolitan Police said: "We are putting together an advice file now on the circumstantial evidence we have got so far. We are very optimistic; we will not give up."
Joyce Osagiede, 32, was arrested in Glasgow last year in connection with the killing but has since been deported to Nigeria. Her estranged husband is being held in Dublin awaiting extradition to Germany in connection with human trafficking offences.Reuse content