Solved: Case of the disappearing headdress, the Mona Lisa of Peru

One of South American's most valuable art treasures, missing for 20 years, has been recovered by Scotland Yard in an extraordinary operation involving murder and double dealing.

The artefact is an ancient Peruvian headdress considered a national treasure and worth more than £1m.

The stunning gold mask disappeared in 1988, after a tomb in the Jequetepeque valley in northern Peru was excavated and its contents trafficked on the black market.

The 3ft-wide headdress was recovered largely thanks to the unorthodox methods of a maverick art specialist, who switched from selling fake masterpieces to recovering stolen ones.

The Peruvian treasure depicts the image of a sea god - the headdress symbolises a mythical octopus with a stylised human head displaying cat-like features.

It is an example of ancient Mochica-civilisation art dating back to 700AD - before the Incas - and is regarded as one of the most important artefacts in Peru's cultural heritage.

Like thousands of other Peruvian antiquities, the mask is thought to have been trafficked in the international black market for stolen art works.

It is believed to have ended up in the hands of a Peruvian dealer called Raul Apestiguia who was murdered in 1996 and his home was ransacked. The headdress next appeared on the black market for sale by a notorious Latin American dealer, with another 41 stolen artefacts.

It is at this stage that a controversial Dutchman called Michel van Rijn became involved. Mr Van Rijn, who is based in London, once specialised in stealing and smuggling works of art, but now claims to expose bent dealers.

He used his website to highlight the stolen headdress. Mr Van Rijn said yesterday that he was contacted by the dealer, who offered the headdress as a bribe in return for taking his details off the website. "The dealer is well connected to high society in the UK - he has his own polo team - and didn't like all the bad publicity," said Mr Van Rijn.

Mr Van Rijn contacted the authorities in Peru, who in turn got in touch with Scotland Yard via the international police agency Interpol in the city of Lima.

Officers from the Metropolitan Police's Art and Antiques Squad struck after the illegal trader handed the piece over to a lawyer in London for safe-keeping. The headdress was seized, but the dealer escaped and is currently under investigation by Scotland Yard and the Peruvian police.

Peruvian officials are due to retrieve the headdress from Scotland Yard this month.

Dr Walter Alva, director of the Royal Tombs of Sipan Museum in Peru, described the seizure as "a very important moment in the worldwide war against illicit art and the looting of my country".

"No ornament of similar quality can be found in any Peruvian museum," he said.

The full role that Mr Van Rijn played is unclear. In the past he has claimed to have operated as an undercover agent for Scotland Yard in return for protection for his own illegal activities. Official sources, however, have confirmed Mr Van Rijn's story. Commenting on the dealer he claims was trying to sell the headdress, he said: "Hopefully he will be arrested soon. If they catch him in Peru they will hang him upside down."

He added that as soon as Scotland Yard gives him the go-ahead he will reinstate details of the alleged offender on his website.

He said of the headdress: "It is Peru's Mona Lisa. It is impossible to put a price on a piece of history and world heritage such as this, because they never come on the market, but should it do so, it could potentially reach in excess of £1m."