Indonesia murder trial: 'I have no doubt that she is capable of ... killing another person'

It's been described as "Indonesia's trial of the century".

Jessica Kumala Wongso, an Australian permanent resident, is accused of murdering her former Sydney design school classmate and friend Wayan Mirna Salihin, who collapsed and died after drinking an iced coffee at a Jakarta cafe in January.

Prosecutors allege the 27-year-old decided to kill the victim with cyanide after Mirna, also 27, advised her to break up with her Australian boyfriend Patrick O'Connor because he was allegedly on drugs.

60 Minutes delved into the case on Sunday evening, as the media circus surrounding the trial intensifies - the courtroom tends to have at least 15 cameras at any one time and there is now a "live Jessica Wongso trial show" on Indonesia's Kompas TV.

The murdered girl's twin sister Sandy Salihin told 60 Minutes' Ross Coulthart she believes Wongso is "enjoying the media" surrounding the trial and can't believe how "happy" Wongso appears to be about her current situation.

"I think she's enjoying the attention. I think she likes the attention because she doesn't have that, maybe ... Yeah, I think she's enjoying the media".

She also believes that Wongso was motivated by envy.

"She's jealous of Mirna because maybe Mirna have a good life ... she just married and she have a good future ahead of her, and maybe Jessica's life is crap," she tearfully told Coulthart on camera.

According to various sources, things started to go off track between the friends two years ago when Mirna (who had moved back to Indonesia following her studies) holidayed in Sydney and caught up with Wongso. But the two women clashed over a meal when Mirna gave Wongso frank advice to dump her then boyfriend.

Mirna's husband, Arief Soemarko, said after the dinner his wife became cautious of Wongso.

"After that meeting, she grew a fear of Jessica, like, she don't want to meet her face-to-face just the two of them. She wants someone to accompany her," he told 60 Minutes.

Following the falling out, Wongso's behaviour in Sydney became more and more troubling.

She was hospitalised five times last year after self harming.

In August she crashed her car into a Leichhardt nursing home only metres from the bedrooms of dozens of elderly residents. Police were of the opinion she had been drinking.

Soon after Wongso's accident, Mirna and Soemarko married in Bali. He is of the opinion their wedding sent Wongso into a jealous rage.

"Because Mirna grew cautious of Jessica, we didn't invite her to the wedding," he explained.

Days after the wedding, back in Sydney, Wongso was sacked from her job with NSW Ambulance.

She then returned to Jakata and made plans to catch up with Mirna and another Australian college friend, Hani Juwita.

On January 6 this year, they agreed to meet up at Olivier, a cafe in an up-market Jakarta shopping centre. Strangely, Wongso messaged her friends hours before, insisting she pre-order their drinks.

Wongso's arrival at the cafe was caught on CCTV at 3.30pm - more than 90 minutes before her friends were due to arrive.

Wongso can be seen leaving the restaurant soon after she gets there. She says she left to buy presents for her two friends. She is seen returning with three large bags, each containing a small bottle of liquid soap.

She then places the large bags at the edge of the table - police say she did this to obscure the view of the security cameras.

About an hour before her friends arrive, Wongso orders an iced coffee and two other drinks and places them behind the paper bags. This is when police say she laced Mirna's drink with cyanide.

Within moments of sitting down, Mirna takes a sip of her iced coffee. Soon she is frothing at the mouth.

Police claim the footage shows Wongso calmly watching on as Mirna take her last gasps of breath. As Mirna's twin sister points out, "she is the only person who is not crying".

Wongso then asks the cafe staff what they put in her friend's coffee. The accusation unnerved the staff member on duty, so they kept the cups and their contents ... without realising it, they were retaining what would be a vital piece of evidence in a murder case.

Wongso's defence lawyer Otto Hasibuan is focusing on autopsy results that show no cyanide was found in any of Mirna's organs other than her stomach. But one of the world's top toxicologists, Australian Professor Ian Whyte from Newcastle's Calvary Mater Hospital, told 60 Minutes that's not at all unusual - the fact that there is no cyanide found in the heart, brain, lungs or liver three days afterwards doesn't indicate there was no cyanide used to murder that person.

Timothy Marbun, who hosts the live coverage of Wongso's trial on Indonesian television, says there's one other "big missing link" in the case.

"There is no cyanide on [Wongso], there is no instance of her putting anything in the drink. She did touch the drink, she did move the drink, but moving a drink doesn't kill anyone," he explains.

A damning assessment of Wongso's character comes courtesy of her former boss Kristie Carter, the head of media and marketing at NSW Ambulance in Sydney.

A statement from Carter to Indonesia police was read out by prosecutors at Jakarta District Court on Tuesday morning, following a marathon hearing.

In the statement Carter described Wongso as a woman with "two personalities".

"At one time, I saw Jessica as someone kind, who loves to smile and suddenly she could be someone quick to anger when someone didn't follow what she wanted.

"I have observed her for the last eight months. And from her attitude, hatred, and nature of her craziness, I have no doubt that she is capable of hurting or killing another person," she said.

Carter told Indonesian police that Jessica once admitted to knowing how to use poison to kill. It happened when she was in hospital, recovering from one of her incidents of self harm.

"I visited her. She said, 'I want to go home. They're treating me like I killed someone. If I wanted to kill someone, I'd know exactly the right dose.'"

Then, just two months before Mirna's death, Carter received a death threat.

"Jessica threatened me by saying, 'You have to die, and your mum should die too.'"

Her comments are part of a dossier on Wongso collected by the Australian Federal Police and handed over to their Indonesian counterparts.

Australian Federal Police only co-operated with the Indonesian police on the promise that a guilty Wongso would not be sent to the firing squad.

But according to 60 Minutes the judges have made it clear that they don't see themselves as being bound by any such undertaking.

Mirna's twin sister is certainly hoping for the death penalty:

"I would like to see justice for my sister and eye for an eye ... You know what I'm saying? Like, it's ... A life for a life".

A verdict is expected later this month.

- Additional reporting: Megan Palin