Detectives have vowed to catch the killers of the boy whose mutilated body was found in the River Thames a year ago.

Speaking at a memorial service for the boy, who has been named Adam, officers said they were also determined to find his real name.

About 30 police officers, scientists, pathologists and other experts involved in the case attended the service at City Hall in London on Saturday.

The boy, who is believed to be of African origin, was discovered in the river near Tower Bridge.

Just imagine your worst nightmare and that would be nowhere near

Commander Andre Baker

He is believed to have been the victim of a ritual sacrifice, of a kind practised in Africa.

Detective Inspector Will O'Reilly gave a reading from the Bible and the leader of the investigation, Commander Andre Baker, gave the address.

Mr Baker said: "We are determined to find Adam's real name, to find his family and to find the people who murdered him."

Mr Baker said he believed Adam's murderers had planned the killing.

"Just imagine your worst nightmare and that would be nowhere near," he said.

"We strongly believe Adam was murdered in London, but know he was from another country."

Celebrate life

The murder investigation was one of the most difficult the Metropolitan Police had ever handled, he said.

There have been leads in Holland but Mr Baker said the most recent have led them to West Africa.

Canon Barry Wight, senior chaplain of the Metropolitan Police Service, finished the service with a short silence to celebrate Adam's life.

After the ceremony Mr O'Reilly and John Azah, from an independent advisory group, laid a wreath from a boat at Tower Bridge, near to where the body was found.

Voodoo killing

A woman from Glasgow arrested in connection with the murder has been bailed by the Metropolitan Police to return to a south London police station in October.

The finding of the body last year sparked a major police inquiry.

The investigation reached as far as South Africa and included an appeal by Nelson Mandela.

The boy is thought to have been five or six years old when he died.

Police are investigating the theory he had been subject to a West African style voodoo killing or a "muti" murder - a ritual killing commonly associated with South Africa.