A BRITISH model was put up for auction on the internet with a starting bid of USD$353,000 (A$445,000) after being kidnapped and drugged when she showed up to a sham photoshoot in Milan.
Police said in a statement the 20-year-old Briton had arrived in Milan on July 10 for an alleged photo shooting arranged through her agent.
Her captors then dropped off the model July 17 at the British Consulate in Milan.
A polish national who lives in the United Kingdom has been arrested on kidnapping charges.
Her kidnapper allegedly threatened to auction her on the internet while trying to extort €300,000 (£270,000) from her agent.
Herba, who is reported to now live in the West Midlands, is accused of luring the woman to Milan from Paris with a promise of a fake photoshoot.
Police said no one took part in auction and it was unclear if Herba was serious about the plan or whether he was a "fantasist".
She arrived at an apartment the following day for the shoot, where she was attacked by two men, say police.
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They are not ascribing a motive to the attack now , with German media suggesting terror and robbery as possibilities. The police said they received a call that a man was attacking people with a knife and a bat in the city of Matsudo.
Prosecutors in Italy said Herba was linked to the Black Death criminal organisation that works on the dark web.
As she was released on July 17th, her captor told her: "Our rules exclude mothers".
The woman was eventually released after six days in captivity when he kidnapper realised she had a child.
Officers went through Herba's phone and computer and said they found photos of the woman and material stating she was for sale, while hair from both the model and Herba was found in the boot of his vehicle.
Italian investigators are now working with their counterparts in Britain and Poland to identify any accomplices involved in the abduction.
Police said they were not sure if the group actually existed.
The woman, whose identity has not been revealed, was held prisoner for a week after being drugged, authorities said.