Information sharing has played a key role in bringing back corrupt officials who fled abroad to avoid trial, Ding Guping, director of the anti-corruption bureau at the Shanghai People's Procuratorate, said on Thursday.

Anti-graft officers have analyzed big data collected from various sources to learn about the movements of suspects, Ding said during a media briefing on the hunt for such fugitives since the launch of operation "Sky Net" in March last year.

Sky Net was launched by the Chinese government, aimed at tracking down corrupt officials hiding abroad and confiscating their ill-gotten assets.

A total of eight corrupt officials have been brought back to face trial from six countries - the United States, Canada, Australia, Thailand, Japan and Singapore - and more than 15 million yuan ($2.22 million) in illegal funds has been seized, according to the bureau.

Ding said it cooperated with the police department, the state security bureau and the immigration inspection authority to obtain information, such as conversation and transaction records from popular messaging app WeChat and mobile payment service Alipay.

Cai Guozhen, deputy director of the bureau's central office, said people always leave traces of their daily lives, which are recorded on surveillance cameras in buildings, on roads and in convenient stores, and through purchases they make. "The key is how to integrate the information," he said.

Ding said anti-graft officers formulated a specific plan for each case after analyzing such information.

For example, Sun Jin, former general manager of the sales department of a futures commission company in Shanghai, who fled to the US in the 1990s after being suspected of embezzlement of public funds, became a US citizen and changed his name and identity. However, through big data investigation and tracking, anti-graft officers determined his identity and captured him when he checked in at a Shanghai hotel using his US passport.

Big data analysis also helped officers to track down Liang Kaifeng, a high-ranking official at a Shanghai-based State-owned enterprise specializing in papermaking. Liang was suspected of taking bribes and fled to the US, but was identified on a flight from the US to Shanghai in May.

Cai said 21 corrupt officials from Shanghai who fled the country have not been captured, and most of them are in hiding in the US, Canada and Australia.

He said it is difficult to bring them back from such countries due to a lack of bilateral extradition treaties and differences in laws, but added that it will become less difficult with increased international cooperation.

"Consensus was reached on anti-corruption cooperation to help bring fugitives back to their home country during the G20 Leaders Summit in Hangzhou, capital of Zhejiang province, in September. The group's first anti-graft research center was set up in Beijing recently," he added.