Thai police release possible Bali nine witness

A Thai woman who could supply critical evidence in the case of the nine Australians accused of trying to smuggle heroin out of Bali has been set free by Thai police.

It was reported today that Thai police arrested the woman, believed to be in her 20s, when she tried to re-enter Thailand from Malaysia.

However, Thai police say they were forced to let her go when Indonesian investigators, sent to pick the woman up, did not have proper extradition documents.

Australian Federal Police Commissioner Mick Keelty said the woman might enable investigators to trace the "Mr Big" of the heroin smuggling syndicate.

"I've said all along that the focus for us is going to be on the wider chain involved in this," he told ABC radio, which carried the report of the woman's release.

"And it needs to be. We're aware and the Indonesian national police are aware of her alleged role in the syndicate," Mr Keelty said.

The news came as Australia's federal police finished their analysis of the drugs involved in the Bali nine case and concluded that the heroin came from Burma.

The ABC report said the woman stayed at a Kuta hotel in April, checking out on the day the nine Australians were arrested.

While initially police thought her role might have been to courier the drugs to Indonesia, it's now thought she might have had a more important role because she made numerous trips in the region.

Mr Keelty said he met the Royal Thai Police this week and impressed upon them the importance of pursuing the woman.

"The fact that she's a Thai national and the fact that we believe that the transiting of the drugs was most likely through Thailand - she does become an important player," he said.

Earlier this week Indonesian police wrapped up investigations into the nine Australians suspects and asked prosecutors to seek the death penalty for the whole group.

The case will be split into six separate trials.

Bali police chief General I Made Pastika said evidence dossiers on all the Bali nine were handed to the prosecutor's office a week ago and they had asked prosecutors to lay charges under section 82 of Indonesia's drug law, which carries the death penalty for trafficking.

The Bali nine - eight men and one woman - were arrested in April following raids by Indonesian police after a tip-off by Australian Federal Police.

Nabbed at Bali airport waiting to board a plane with 8.3kg of heroin strapped to their bodies were Brisbane youngsters Michael William Czugaj and Scott Anthony Rush, both 19, Wollongong man Martin Eric Stephens, 29, and Newcastle woman Renae Lawrence, 27.

Sydney man Andrew Chan, 21, was arrested on board a Sydney-bound plane. He allegedly helped organise the operation and threatened the couriers, saying if they did not carry out their roles their families would be killed.

Police later swooped on Kuta's beachfront Melasti Hotel, confiscating 300g of heroin and narcotics equipment and arresting four others: alleged ringleader Myuran Sukumaran, 24, and fellow Sydney residents Si Yi Chen, 20, Matthew James Norman, 18, and Tach Duc Thanh Nguyen, 27.

The head of Bali's narcotics unit, Colonel Bambang Sugiarto, said the four alleged couriers caught at the airport would face court as a group.

- AAP