Police in South Africa yesterday sought to establish the origin of diamonds at the heart of Naomi Campbell’s testimony at the war crimes trial of former Liberian leader Charles Taylor.

“Our enquiry needs to determine that fact and that is what we are going to be busy with,” Musa Zondi, spokesman for the South African police special investigations unit, said.

“Possession of uncut diamonds is an offence. Ours is to search for truth and we are investigating the offence and who might be responsible.”

Ms Campbell testified last Thursday that she had received “dirty-looking stones” after a dinner she attended in Pretoria in September 1997 that was hosted by then President Nelson Mandela, with Mr Taylor among the other guests.

Assuming they were from Mr Taylor, she gave the stones to Jeremy Ratcliffe, then director of the Nelson Mandela Children’s Fund, who held onto them until last week when he turned over the three small uncut diamonds to the police.

Investigators have confirmed they are diamonds, but their origins remain a mystery.

Prosecutors at the Special Court for Sierra Leone want to prove that Mr Taylor, 62, dealt in so-called blood diamonds to buy weapons for rebels who murdered, raped and maimed civilians during Sierra Leone’s 1991-2001 civil war. Mr Taylor denies the allegations.

In a statement, Mr Ratcliffe said he accepted the stones from Ms Campbell because “I thought it might well be illegal for her to take uncut diamonds out of the country”.

While Ms Campbell wanted the charity to make use of the stones, Mr Ratcliffe said he did not want to involve it in possible illegal activities, adding: “In the end I decided I should just keep them.”