Sounding bold and strong, she said she had never admitted to possessing any marijuana and that the official indictment must be a mistranslation. Yet the brave front soon began to dissolve in the main courtroom, when she sat in a little stool before the judges' bench and heard the grave charges levelled against her.

Three Balinese judges have now begun the long process of deciding whether the 27-year-old beauty school student from Tugun on the Gold Coast is guilty of trying to bring 4.1kg of marijuana into Bali on October 8, 2004. She faces a maximum penalty of death if found guilty.

It has been a long and emotional journey for the Corby family and their friends on the Gold Coast. It began in Brisbane, when Schapelle, her 17-year-old half-brother James and two friends boarded a Qantas flight to Sydney and continued on an Australian Airlines flight to Bali. It was a long-anticipated break for everyone and the chance to join a birthday party planned for Schapelle's sister Mercedes, who was on an extended visit to Bali with her Balinese husband Wayan and their two children.

When their baggage was off-loaded at Bali's Ngurah Rai airport, a customs official manning the external X-ray machine noticed something strange in Corby's unlocked body-board bag. She looked nervous, according to the official indictment and at first refused to open the bag. After she had been ordered to open and empty it, the official saw a transparent plastic sack the size of a pillow-case full of prime marijuana heads inside another plastic sack.

Her first full day in police detention was agonising. She vomited from the shock, her lawyer Lily Lubis says, and cried until her eyes were swollen. Bali police and prosecutors say they have a strong case against her, stemming primarily from her ownership of the bag. It all comes back to that, they say: when she admitted she owned the body-board bag, she admitted responsibility for the contents – a body-board, a pair of flippers and a plastic sack of marijuana.

Yet there was a surprise allegation in the indictment read to the court yesterday which could cruel the prosecution. It stated Corby had admitted to owning the marijuana when her bag was first examined at Bali airport. Asked what the contents of the plastic sack were, she allegedly said "it's marijuana", which is a long way from admitting it was hers. Bali's drug squad chief, Colonel Bambang Sugiarto, suspects the customs officials may have extrapolated her guilt from her recognition of the plant.

Important questions remain unanswered in this knotty case. Experts estimate the stash could have cost as much as $30,000 and would sell for far more on the street. Schapelle's family is not wealthy – $30,000 would be hard to come by. How could the plastic sack of drugs have remained undetected in Brisbane and Sydney airports in this era of strict security tightened by fear of terrorism? Why smuggle marijuana from Australia into Bali, where drugs are inexpensive and easy to get? Why, most importantly, risk the death penalty which applies to heavy drug offences in Indonesia? Three drug-smugglers were executed in Indonesia last year and the government is on a get-tough binge.

Indonesia is endemically corrupt, regularly languishing at the bottom of Transparency International's global corruption index, and Indonesian police have been known to shake down foreigners in their custody. Corby's lawyers have investigated the possibility that someone may have planted a package of cannabis in her luggage.

Yet the pieces don't seem to fit together. The marijuana was of Australian origin, extremely valuable, and found in the bag of a woman who would never be called wealthy. A foreign scalp in the drugs war may be seen as an important win for the Indonesian police, but many foreigners are arrested for drugs in Indonesia every year.

The beauty school student has consistently claimed she is innocent and a troop of friends and relatives have backed her all the way. Her sister Mercedes has stayed in Bali for months to be close to Schapelle. Her mother, Ros Corby, was in Bali yesterday for the trial opening. A television network had apparently sewn up a deal with the Corbys: they would talk to no one except one TV crew.

Jodi Power Photo: Channel Seven

Jodi Power, a close friend of the Corby family, was also in court yesterday. She has sacrificed a lot to come to Bali to support Schapelle, who she has known for 13 years. She brought her two children, aged two and eight, on an eight-week trip to Bali and she takes them to the prison twice or three times a week to visit her friend. She takes food to Corby, such as vegetarian sandwiches on rye bread, and tries to talk about other things.

"Ever since I have known her, and I swear on my children's lives, I have never seen her smoke marijuana, she doesn't like the stuff," says Power, who has set up a fund for her friend's financial needs. "It is ridiculous to link Schapelle with expensive drug-running. She worked triple hours at her brother's shop to get here to Bali. She worked so hard to be able to afford to come over for her sister's birthday."

A Balinese law firm has been retained to defend Schapelle, and lawyer Vasu Rasiah publicly demanded the technical assistance of the Australian Federal Police for an in-depth forensic analysis of the drugs and the plastic sacks. Fingerprints on the outer plastic sack were compromised when it was handled by customs officials and police, but Rasiah said the origin of the sack might be determined. Yesterday he said he would demand the drugs be properly tested.

Yet the AFP cannot simply barge in on an Indonesian case, and a spokeswoman has made it very clear Australian assistance has not been requested by Indonesia, except for information on whether or not Schapelle had a criminal record. "AFP can confirm that a formal letter offering assistance was provided to the Indonesian National Police in relation to the Schapelle Corby investigation," an AFP spokeswoman said.

Corby's lawyers travelled to Australia late last year in search of evidence and met Foreign Minister Alexander Downer, who agreed that assistance would be offered to the Indonesian police. However, Balinese police maintain they require no help and they have conducted an investigation which provides enough evidence for the prosecution to proceed.

Last year, when the investigation was in full flight, drug squad chief Colonel Sugiato said the marijuana was probably from Australia, and commonly called "lemon juice" in Bali, where it sells for up to 10 times as much as the local drug. Indonesia classes marijuana as a Group 1 narcotic, along with heroin. Whereas Indonesia prescribes death for drug traffickers, an offender caught trying to bring 4kg of marijuana into Australia might be sentenced to 10 years in prison.

"We know everyone is talking about the death penalty in Australia but we are not thinking about that as a possibility. We are more worried about her spending one more day in that jail," Mercedes told an Australian magazine.

Notoriously home to the core Bali bombers, the prison also holds a large number of drug offenders. Mercedes has seen the bombers while visiting her sister. "I saw him (Amrozi) smile at me – that horrible, menacing smile," she says. "They call Schapelle an infidel."

Before Corby was transferred to Kerobokan prison she was detained in the lock-up for several weeks, where she slept on a mat in a cell. Yesterday, though, she looked healthy and robust, despite nearly four months of incarceration in dingy cells.

Visited nearly every day by Mercedes, or her friend Jodie, she kept her spirits up by reading magazines and chatting with the Australian incarcerated in the next door cell, Queenslander Chris Currell. Escorted backwards and forwards from her cell in the lock-up to the interview room, she was regularly bombarded with questions by waiting journalists. "Help me," she said on one particularly bad day. "Help me."

Sian Powell is The Australian's Jakarta correspondent.