ROME (AFP) - A hunt for possible accomplices to the terrifying abduction of a British model in Italy was underway on Sunday after the alleged mastermind told police he planned to auction her off as a sex slave on the dark web.

Italian police have confirmed they are looking for at least one other man following the arrest of British-resident Pole Lukasz Pawel Herba, 30, on charges of abduction and illegal imprisonment.

According to Italian media reports, citing leaked files from the investigation, the 20-year-old mother has told police she saw two men and was aware of three others but never saw their faces during her week-long ordeal in July.

The model, who returned to Britain on Sunday (Aug 6), was drugged and kidnapped on July 11 after going to what turned out to be a set-up photo shoot in downtown Milan.

"Somebody wearing black gloves came up from behind me and put one hand on my neck and the other over my mouth, while a second person wearing a balaclava injected me in my right arm," the woman, was quoted as telling police by Italy's Corriere della Sera, which named her as Chloe Ayling.

After a three-hour journey from Milan to a remote mountain village, the model was held until July 17, spending most of her time handcuffed to furniture while her abductors considered their options.

Many details of the extraordinary case remain unclear, although police have confirmed that the victim was injected with the tranquilliser ketamine and said they believe Herba may have been capable of causing her serious physical harm.

However, his account of events in other respects has been described by the prosecutor in charge of the case as barely credible.

Detectives are unclear as to whether Herba was involved in a credible attempt to auction his victim or if it was an elaborately staged threat intended to extort a ransom from the model's agent and family.

No one took part in the online auction, so it was unclear if Herba had the necessary contacts to organise such an operation of was something of a fantasist, according to the police.

"Fantasist or not, what is clear is that he is a very dangerous man who drugged his victim as soon as she was kidnapped and put her inside a large travel bag in the boot of a car," Milan deputy prosecutor Paolo Storari told a press conference on Saturday.

"His version of events is barely credible but clearly he does not deny that he was with her for the time she was missing," Storari said.

On July 17, for reasons that are still not clear, Herba drove the woman back to Milan and released her close to the British Consulate, where he was arrested.

He had told the model that he could not go on holding her because she was a mother of a young child and such abductions were prohibited by "Black Death", a nefarious web-based group he claimed to belong to.

Police are not sure the group actually exists or if Herba's depictions of it are accurate. Investigations are continuing in collaboration with police in Britain and the suspect's native Poland.

Ayling told reporters at her home in south London Sunday that she had feared for her life throughout the "terrifying experience".