AN AUSTRALIAN resident dubbed ‘the coffee killer’ might have been “jealous” of a friend she has been accused of fatally poisoning in Indonesia.

Jessica Kumala Wongso, 27, has been charged with premeditated murder after allegedly lacing former Sydney student Wayan Mirna Salihin’s iced coffee with cyanide in a Jakarta cafe while on holidays.

A consultant to the Indonesian police investigation who interviewed Ms Wongso, and other key figures in the murder case, said she might have been acting out of jealousy.

news.com.au exclusively reported last month that Ms Wongso was an Australian resident who worked for NSW Ambulance after studying at Sydney’s Billy Blue College of Design with Mirna.

According to forensic hypnotist Kirdi Putra, the two friends drifted apart and did not see each other for at least five years.

He told the ABC that some of Ms Wongso’s friends became closer to Ms Salihin before she married in Bali late last year.

Ms Wongso was not at the wedding

“A possible motive is some kind of jealousy and revenge,” Mr Putra told ABC’s 7.30.

“First, her friends get taken away, second one, (Ms Salihin) got a better life than (Ms Wongso’s) life — that could be a motive.

“It’s not quite strong enough, that’s why I ask the police to check Jessica’s psychological profile to understand more.”

The AFP told news.com.au it was assisting Indonesian authorities with the investigation.

Ms Salihin died in Jakarta after having an iced coffee with Ms Wongso and another friend, Hani, at the Olivier cafe at the Grand Indonesia shopping mall in February this year.

Police have accused Ms Wongso of lacing Ms Salihin’s drink with cyanide after the newlywed reportedly sipped the iced coffee then started convulsing. She was rushed to hospital and died that day.

Ms Wongso, who denies involvement in Ms Salihin’s death, was the one who ordered the drink that killed Ms Salihin, according to police.

Mr Putra told the ABC he examined instant messages sent between the pair and interviewed friends of both women and Ms Salihin’s grieving husband.

He said there was no evidence supporting speculation in Indonesia that the women were lovers.

“I don’t see any supporting materials on their conversations in WhatsApp (an instant messaging service) or their gestures ... or based on information gathered by her husband and friends,” he said.

He has prepared a report on the case for Jakarta detectives.

If found guilty, the charge carries a minimum jail sentence of 20 years and a maximum penalty of life in prison.

Indonesian authorities and Ms Salihin’s family have publicly said they would not seek the death penalty.

A source close to the accused told news.com.au last month that Ms Wongso was on holidays in Indonesia with her parents and was due to return to work as a graphic designer in Sydney just weeks after her arrest.

news.com.au exclusively revealed that Jessica, her parents and two siblings have been permanent residents of Australia since emigrating from Indonesia about eight years ago.

The family resides in Sydney.