Police yesterday finished their investigation of four Rio Tinto Group executives, including Australian Stern Hu, and sent the case to the local prosecutors.

A spokeswoman for the Australian Department of Foreign Affairs and Trade told China Daily in an e-mailed statement that Beijing had informed Australia's Consulate-General in Shanghai that the investigation phase of the case had concluded.

Xinhua also reported last night that Chinese police had finished a five-month investigation into the case, and four suspects, including Hu, were handed over to prosecutors yesterday. Local officials said a press briefing will be held next week regarding the case.

The Australian spokeswoman said Shanghai People's Procuratorate will decide whether the case should be brought to trial.

"We are not in a position to say how long this phase of the case will take, and are not prepared to speculate about the outcome," she said.

The investigation of the case lasted five months, which is three months more than a normal case.

Hu, the Shanghai-based head of Australian Rio Tinto's iron ore operations in China, along with his three Chinese colleagues, were detained by the government last July on suspicion of stealing State secrets.

A month later, officials from the Shanghai Municipality Public Security Bureau formally arrested the four on suspicion of violating commercial secrets and taking bribes as an individual not employed by the state.

The spokeswoman added that the details of the charges are not likely to be known until the prosecutors decide to take the case to trial.

Hu's possible charges of infringing trade secrets could bring him a maximum seven years in prison, and his company will have to pay damages, Jing said.

Scholars say the case will not affect the bilateral ties between China and Australia.

Han Feng, observer of Asia-Pacific Studies with the Chinese Academy of Social Sciences, said although the two sides had some misunderstandings regarding Hu's case in the beginning, now they have reached a consensus and the Chinese law was respected during the course of the investigation.

Australian Foreign Minister Simon Crean told the Australian Broadcasting Corporation yesterday that the case is being handled according to Chinese laws and he is confident that China will adhere to its legal obligations.

"The Chinese side must have had enough evidence, otherwise they wouldn't have detained the executive," Han said.

The Sino-Australian tie has been properly maintained and will likely improve this year since the economy is recovering in both countries, he said.