A police officer displays a bottle of fake wine at a news conference in Shanghai's Hongkou district on Wednesday. Provided to China Daily

Shanghai's Hongkou district police - assisted by big data provided by Alibaba, China's e-commerce behemoth - have cracked the largest case involving fake Australian wine ever handled in the city.

More than 14,000 bottles of fake Penfolds wine valued at 10 million yuan ($1.5 million) were involved, the police said on Wednesday. Thirteen suspects have been detained, including a man surnamed Dai who achieved sales worth 1.2 million yuan for three months in a row through an online shop on Alibaba's Taobao. Another man, a supplier surnamed Su, was also detained, the police said.

Police said they were alerted in August by Alibaba that a Taobao shop was suspected of selling fake Penfolds wine. Officers purchased wine from the shop and found its quality obviously inferior to the genuine product, from the printing on the package to the quality of the bottles and ingredients.

"Penfolds reported to us that they found suspicious retailers on our platform charging extraordinarily low prices for their products," said An Ti, a member of a task force in Alibaba's platform governance department.

"We analyzed the online shop with our data model and determined that the shop was based in Shanghai's Hongkou district," she said.

Xie Yijun, who directs the food and drug crime investigation team of the Hongkou police, said Dai was selling bottles of wine at about 200 yuan in the online shop, while the normal price should be between 600 and 3,000 yuan, Xie said.

On Sept 1, police detained Dai and another five suspects at a warehouse in Shanghai from which they were operating the online shop and storing the fake wine. More than 2,000 bottles of fake wine were found.

Police said that Dai, who claimed to be a wine retailer for seven years, confessed that he had purchased cases of wine from Su in Xiamen, Fujian province.

On Sept 18, police captured Su and another suspect and found 10,000 bottles of fake Penfolds wine and more than 10,000 fake labels and packages in two warehouses in suburban Xiamen.

"They purchased cheap wine through various channels and repackaged it with fake Penfolds labels in the warehouses," Xie said.

Su sold the wine at between 50 to 60 yuan per bottle to Dai, the police said.

Later, another five suspects - either online retailers like Dai or others who purchased from him in large amounts and distributed the wine to pubs and karaoke bars - were captured by police together with 2,000 bottles of knockoffs.

"The assistance from Alibaba played a key role in cracking the case. This is a successful example of good cooperation between the police and a business. We look forward to a stronger collaboration to achieve more success in combating crime," Xie said.

Dai admitted selling some of the fake wine through posts on WeChat Moments. "Su had approached me earlier this year with wines that were below market value. I had regular customers who liked cheap wines, sometimes the cheaper the better," Dai said in an interview with China Daily while in detention.

zhouwenting@chinadaily.com.cn