An Australian woman was on Monday convicted of murdering three elderly relatives of her estranged husband with a meal laced with poisonous mushrooms, and attempting to murder a fourth, in a case that gripped the country.

Erin Patterson, 50, was charged with the murders of her mother-in-law Gail Patterson, father-in-law Donald Patterson and Gail’s sister, Heather Wilkinson, along with the attempted murder of Ian Wilkinson, Heather’s husband.

The four had gathered at Erin Patterson’s home in Leongatha, a town of about 6,000 people some 135 km (84 miles) southeast of Melbourne, where the mother of two served them individual Beef Wellingtons that were later found to contain death cap mushrooms.

On Monday, the jury in the case found her guilty of all four charges.

Patterson had pleaded not guilty to all charges, saying the deaths were accidental. She will be sentenced at a later date and faces a maximum life sentence.

The 10-week trial in Morwell, a town around two hours east of Melbourne where Patterson had requested the case be heard, attracted huge global interest. Local and international media descended on Court 4 at the Latrobe Valley Magistrates’ Court the nearest court to Patterson’s home, despite being warned of lengthy delays.

State broadcaster ABC’s daily podcast on proceedings was consistently among the most popular in Australia during the trial, while several documentaries on the case are already in production.

MAJOR DECEPTION

Key facts in Australia’s mushroom murder trial

THE TRIAL

The ten-week trial began on April 29 in Morwell, a former coal mining town about two hours east of Melbourne.

Overseen by Justice Christopher Beale, it generated huge interest in Australia and internationally, with the six seats in court reserved for the media allocated in a daily ballot. Members of the public queued each morning to be able to watch proceedings from the gallery.

Public broadcaster ABC’s daily podcast on the proceedings was the country’s most popular for much of the trial, while streaming service Stan has commissioned a documentary on what it says is “one of the highest profile criminal cases in recent history”.

Patterson will be sentenced at a later date. The charges carry a maximum life sentence.

PROSECUTION

The prosecution, led by Nanette Rogers, spent a month laying out its case against Erin Patterson.

Rogers told the court that the accused had foraged for the death caps, dried them and measured out a “fatal dose” on her kitchen scales before adding them to her guests’ Beef Wellingtons, ensuring her own food was untainted.

It was all part of a “sinister deception”, Rogers argued, saying Patterson had lied to police when asked whether she had ever foraged for mushrooms or owned a food dehydrator, which was later found in a landfill site and contained traces of death caps.

Dozens of witnesses, including relatives and forensic, medical and mushroom experts, gave evidence for the prosecution.

Among them was Simon Patterson, who told of the couple’s strained relationship in the months before the fatal lunch.

Ian Wilkinson also gave evidence, telling the court the accused had served her own meal on a different coloured plate.

DEFENCE

Erin Patterson’s defence, led by barrister Colin Mandy, did not dispute there were death caps in the meal or that she had lied to police about key details such as foraging for mushrooms.

But Mandy told the court the deaths were a “terrible accident” and that while the accused might have had “spats and disagreements and frustrations” in her relationship with her estranged husband she had no reason to kill her lunch guests.

Erin Patterson gave evidence in her own defence and spent eight days in the witness box including five days of cross-examination by Rogers.

She was the only witness for the defence.

JURY

Fifteen jurors were initially selected for the trial and 12 were chosen by ballot to take part in the final deliberations.

Justice Beale repeatedly instructed the jury not to conduct their own research on the case, or to discuss it outside the jury room.

One juror was dismissed in May for allegedly discussing the case with family and friends.

Jurors in Australia are not responsible for sentencing and are not allowed to speak publicly after the trial.

The jury returned a unanimous verdict, a requirement for securing a murder conviction in Victoria, the state where the case was held.

The prosecution, led by barrister Nanette Rogers, told the court that Patterson had employed four major deceptions in order to murder her guests.

She first fabricated a cancer diagnosis to lure the guests to the lunch, poisoning their meals while serving herself an untainted portion, Rogers told the court.

Patterson then lied that she was also sick from the food to avoid suspicion, before finally embarking on a cover-up when police began investigating the deaths, attempting to destroy evidence and lying to police, the prosecution said.

Patterson, who said during the trial she had inherited large sums of money from her mother and grandmother, retained a four-person legal team, led by Colin Mandy, one of Melbourne’s top criminal barristers.

She was the only witness in her defence, spending eight days on the stand, including five days of cross-examination.

Patterson told the court about a life-long struggle with her weight, an eating disorder and low self-esteem, frequently becoming emotional as she spoke about the impact of the lunch on the Patterson family and her two children.

She had lied about having cancer not to lure the guests to the lunch to kill them, but because she was looking for their help with telling her children and was embarrassed to say that she actually planned to have weight loss surgery, she told the court.

Patterson had also not become as sick as her lunch guests because she secretly binged on a cake brought by her mother-in-law and then purged herself, she told the court.

The jury of seven men and five women retired on June 30, taking a week to reach a verdict.

Justice Beale gave the jurors in the trial special dispensation to avoid jury duty for the next 15 years, due to the length and complexity of the case.