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.
Based on court documents, the newspaper says she was then drugged, handcuffed and put into a suitcase.
Police have arrested a 30-year-old Polish man - believed to be resident in the United Kingdom - in connection with the kidnapping.
The kidnapper used an encrypted account and then asked the model's agent for $300,000 to stop her from being sold in auction.
The model, who is reportedly in her 20s, travelled from Paris to Milan for the fake photo shoot and was only released by her kidnapper because she was a mother with a young child.More news: Rohani Sworn In For Second Term
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.
Italian media reports that Herba has links to the "Black Death" criminal organisation that works on the dark web.
It has been reported that the captor demanded £50,000 upon the woman's release and threatened to kill her if she told police about the incident.
He has been charged with kidnapping for the purposes of extortion.
Police are now working to identify Herba's accomplices and established what happened to the woman while she was help captive.More news: Duke of Edinburgh waves goodbye to royal duties
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 auto.
The woman was released after being held for six days and investigations are being carried out by authorities in Italy, Poland and the UK.
The Foreign Office said it was providing support to a British woman.
Police said they were not sure if the group actually existed.More news: NASA Jets Plans To Chase Solar Eclipse When Flies Across The US