The gunman, believed by police sources to be a mainland hitman hired by Wan, is still at large.

'The indictment is under preparation, no final decision has been made and the papers are still a matter of judicial secrecy,' a judicial source said.

It is the first time Wan has been publicly connected to the murder attempt.

If it gets the go-ahead, Wan's new trial could start in a matter of weeks. 'Some time after next month's handover,' the source said.

Colonel Apolinario was deputy director of the Macau Government Gambling Inspection and Co-ordination Department when he was shot as he walked to his car from his city centre office on Avenida da Praia Grande.

One bullet passed through his cheek and another through his neck, nearly killing him.

After treatment in Macau and Portugal, he became head of the inspectorate but left Macau for Portugal after several months in charge.

Last month he was flown in from Portugal to give evidence at Wan's trial, telling the court the assassination attempt took place two weeks after Wan had told him the local 14K triad was 'my group'.

Colonel Apolinario, who now commands a Portuguese regiment on the Azores islands, also said Wan was to blame for the 'deplorable' situation in Macau's casinos in the mid-1990s.

Sources say Wan allegedly wanted to get rid of Colonel Apolinario because of his efforts to clean up the casinos.

Lawyers for Wan are considering an appeal against his 15-year sentence.

And those representing younger brother Kuok-hung, 39, and his seven other co-defendants said they were 'ready to appeal' pending discussions with their clients, who received sentences of between 5.5 and 15 years.

Under Macau law both the defence and prosecution have 10 working days from the date of sentencing to appeal to the High Court.

A source in the public prosecutor's office said a decision on whether to launch an appeal over the acquittal of co-defendant Chan Hak-kan would be taken in due course.