Twelve suspects have been detained for allegedly leaking and trading over 10 million items of client data from an insurance company in Shanghai, police said on Thursday.

The suspects have profited over 20 million yuan (US$3 million) from the illegal business, police said.

Police in Yangpu District started their investigation in November last year when the insurance company reported that some work computers of its sales staff had accessed a large amount of client information.

Suspicion soon fell on two salesmen, one surnamed Chen and the other surnamed Liu.From their computers police allegedly found over 1 million items of personal information in Excel forms including identity card numbers, mobile phone numbers and home addresses.

The two suspects allegedly relayed the acquired data via an online shopping website to their accomplice who was disguised as customer service staffer from an online shop.

The insurance company bans its sales staff from using mobile phones at work and accessing websites, except for online shopping websites, police confirmed.

The online shop was run by a man surnamed Yu and another surnamed Ba, former staff of the insurance company who resigned not long ago to establish a business which sold “quality client information” for profit.

The four suspects and eight others involved in the case were caught last month in Pudong New Area and HuainanCity, Anhui Province.

A suspect surnamed Liu, who is now under detention, claimed that he used an account given to him byBa to access the insurance company's database from May to October last year, for which he was paid 30,000 yuan.

Liu had been working for the insurance company for eight years. At the company, staff atLiu and Chen'slevel have no access to the database of client information.

In other cases, Huangpu District police said they have solved five cases of personal information infringement since the beginning of this year. Twenty suspects and over 1.1 million items of personal information were discovered.

Shanghai police said they have solved over 1,300 cases of personal information infringement since last year.

They said most of thecases were reported by companies who discovered the leaks of data themselves, but reminded residents that they are also encouraged to report leaks of their personal information.

Zhu Weiping, a police officer at Nanjing Road E. Police Station, said in some cases former insurance and financial company staff took client information with them when resigning and made use of it when they started working for other companies.

“Usually such companies have strict rules about the secrecy of client information, but sometimes the rules are not well observed,” he said.