The Bali Nine are back in Australia, 19 years after their arrest.

In April 2005, nine Australians were caught attempting to smuggle 8.3kg of heroin out of Indonesia and into Australia. And so became the Bali Nine — an infamous example of what can go wrong when messing with illegal drugs overseas.

Almost 20 years have passed since the day they were caught. And now, the five remaining members of the Bali Nine drug smuggling ring have returned to Australia.

Australian citizens Matthew Norman, Scott Rush, Martin Stephens, Si Yi Chen, and Michael Czugaj have arrived back in the country from Indonesia, the federal government said on Sunday.

The five men have served more than 19 years in prison in Indonesia for serious drug offences.

"We would like to convey our deep appreciation to the government of Indonesia for its co-operation to facilitate the men's return to Australia on humanitarian grounds," Prime Minister Anthony Albanese, Foreign Minister Penny Wong and Home Affairs Minister Tony Burke said in a joint statement on Sunday.

"This reflects the strong bilateral relationship and mutual respect between Indonesia and Australia."

The Australian government had consistently advocated for the men and provided consular support to them and their families.

"The men will have the opportunity to continue their personal rehabilitation and reintegration in Australia," the statement said.

Who are the Bali Nine?

A year after Andrew Chan, Myuran Sukumaran, Matthew Norman, Scott Rush, Si Yi Chen, Michael Czugaj, Martin Stephens, Tan Duc Thanh Nguyen and Renae Lawrence were caught and tried, their sentences were passed down.

Ringleaders Chan and Sukumaran were sentenced to death, while Norman, Rush, Chen, Czugaj, Stephens and Nguyen were sentenced to life in prison. Lawrence received a 20-year sentence after a successful appeal.

Here's what happened to the nine members since that day in 2005.

(Top, L to R) Myuran Sukumaran, Scott Rush, Tach Duc Thanh Nguyen, Renae Lawrence. (Bottom, L to R) Si Yi Chen, Matthew Norman, Michael Czugaj, Martin Stephen and Andrew Chan, at various stages of their trials in Denpasar in 2005 and 2006. Image: Getty.

Andrew Chan.

Along with Myuran Sukumaran, Andrew Chan was found to be the ringleader of the group. This fact determined his punishment. In the eyes of the Indonesian courts, he and Sukumaran deserved harsher sentences than those who followed their instructions.

In February 2006, he was sentenced to death by a firing squad. After appealing to the Indonesia Supreme Court for his sentence to be downgraded, and a last-ditch appeal to the Indonesian president for clemency failed, Chan and Sukumaran's executions were carried out on April 29, 2015.

Myuran Sukumaran.

Myuran Sukumaran was sentenced to death on the same day as his co-ringleader, Andrew Chan. Over the duo's time in prison, they became model inmates, running classes in cooking, art and English and offering their services as counsellors to fellow inmates. But this wasn't enough to convince judges or former Indonesian President Joko Widodo to spare their lives.

Chan and Sukumaran were executed together, along with six other prisoners, by a firing squad. They refused blindfolds and sang a hymn before they were shot.

Renae Lawrence.

Lawrence walked free after serving almost 13 years in Bali's Kerobokan and Bangli prisons. Under Indonesia's leniency program, prisoners can make an appeal to have their sentences reduced for good behaviour and on specified public holidays.

Lawrence had six years shaved off, as well as several months in small blocks. The 47-year-old, who arrived in Australia in November 2018, became the first Bali Nine member to be freed from jail.

Scott Rush.

Scott Rush's parents inadvertently played a large role in the entire group's arrest.

Rush's father, Lee Rush, later said that the Australian Federal Police had been contacted on his behalf alerting them to his fears that his son was going to commit a crime during his upcoming trip to Bali. His parents said they were assured that the AFP would tell their 19-year-old son he was under surveillance to discourage him from leaving. According to Rush's lawyer, they did no such thing, instead tipping off the Indonesian authorities to a possible crime.

In a 2006 interview with ABC's Australian Story, Lee and Chris Rush said: "I feel very let down by our Australian Federal Police — we tried to lawfully stop our son leaving the country, it wasn't done."

Rush was sentenced to life imprisonment in February 2006, but an appeal in September that year saw his sentence surprisingly upgraded to the death penalty. For five years he sat, fearing the worst, until another appeal in 2011 saw his sentence reduced back to life. He was transferred to Karangasem jail in Bali's east in early 2014. Five years later, Rush pleaded for his sentence to be reduced in an emotional letter, where he vowed to become an anti-drugs campaigner.

"I sincerely apologise to the government and citizens of Indonesia for the shameful impact my action caused to the country of Indonesia and its people," the letter read.

Tan Duc Thanh Nguyen.

Tan Duc Thanh Nguyen was 22 when he was arrested as a member of the plot to import drugs into Australia. The Vietnamese-born Australian, often considered the "forgotten" Bali Nine member, was convicted to life in prison over his involvement. After lodging an appeal, his sentence was upgraded to death, but a second appeal reduced it to the original sentence.

However, Nguyen did die while serving time. In June 2018, the Indonesian Corrections Office confirmed that the 34-year-old died in a Jakarta hospital from stomach cancer on May 9.

Before his death, Nguyen did have a brief period of happiness while in prison. In 2015 it was reported he was engaged to Lyudmyla Karpova, a then-26-year-old ambulance volunteer who worked in Italy.

Matthew Norman.

Matthew Norman, the youngest member of the Bali Nine, met his future drug gang peers at the catering company Eurest, where Martin Stephens, Renae Lawrence and Andrew Chan also worked.

Like some of his fellow Bali Nine members, Norman's initial life sentence was bumped up to death upon appeal. But in 2008, Indonesian judges decided to downgrade the death penalties of Norman, Si Yi Chen, and Tan Duc Thanh Nguyen back to life sentences.

In 2016 he told News Corp that he hoped he would be released early and be able to use the graphic design skills he had gained to start a career in Australia.

"I don’t believe I would die in this place. If it [reduction] doesn’t happen this year we try again next year… We are not getting any younger. It would be good to go home soon and start our lives again with all the skills we have learned in here. It would be good to go home and start fresh."

When fellow convicted drug smuggler Lawrence was released, Norman told the ABC:

He went on to say that he was focusing on himself and working to get his sentence reduced.

"I believe that through the Indonesian judicial system, with a life sentence, you have many opportunities to get your sentence reduced, and we've been applying for the past few years to get that reduction," he said.

"We still haven't got it, but we still have hope that we can get our sentence reduced, and that one day we will walk out of here."

Watch: Schapelle Corby returned home in March 2017. Post continues after video.

Si Yi Chen.

Si Yi Chen also experienced two years of thinking he was going to face a firing squad before learning he would spend the rest of his life in an Indonesian prison.

In 2017, he told ABC's Foreign Correspondent he had "complicated feeling" when his life sentence was first upgraded to death.

"It was actually a relief for me, knowing that I’m not going to rot in jail, but my parents told me not to give up," he explained.

"So when I got my sentenced reduced back to life sentence I said okay, look at it as God gave us a second chance to live."

Michael Czugaj.

Micahel Czugaj suffered extreme disappointment when, in September 2006, an appeal decision to reduce his life sentence to 20 years was reversed. In 2016, he was allegedly caught with traces of the drug ice and moved from Kerobokan prison to a prison in Java that he said is a far tougher place to live.

"Every time we found [the drug], it was always only leftovers. We want to prove it directly," said prison officials, per the ABC.

In a 2017 interview, he said he still misses Chan and Sukumaran.

"I had many dark periods over the years and they helped me … took me under their wing," he told Fairfax.

"I miss them. I want to live and I want to get home... for them and for myself."

Martin Stephens.

Martin Stephens was arrested at Bali Denpasar airport where police found 3.3kg of heroin strapped to his body — and for that, he was sentenced to life in prison.

Stephens said during his trial that he was threatened by ringleader Andrew Chan, his supervisor at the catering company where he worked, into going through with the smuggling plan.

"They threatened me. They threatened my family, my friends, my love — my girlfriend… They showed me pictures," he said.

Stephens married Indonesian woman Christine Winarni Puspayanti in 2011, and is currently serving out his time in a Java prison after being moved from Kerobokan prison in 2014.

This article was originally published in November 2018 and has since been updated.

Feature Image: AAP.