An internationally-renowned Australian scientist who was allegedly murdered by her nephew in Argentina "weirdly" stopped replying to daily messages from her friends about two weeks before she was found dead.
The body of 54-year-old University of New England microbiology professor Lily Pereg, who was born in Israel, and that of her 63-year-old Israeli sister Pirhya Sarussi were discovered on Saturday local time near the city of Mendoza.
The bodies were buried on a lot beside the house of Ms Sarussi's son Gilad Pereg, 36, according to Argentina prosecutor Claudia Rios.
Pereg was arrested on Friday and formally charged a day later with the aggravated homicide of his mother and the simple homicide of his aunt following the discovery.
"We the family, are shocked. Gilad Pereg, Pyrchia Sarusi's son, standing accused of murdering his Monther and Aunt [sic]," the women's family said in a statement on GoFundMe.
"We at the family are at owe and humbled by the outpouring of support and love, worldwide. Your love carried us and will help us recover from a huge tragedy. There will never be an explanation."
The family had been using the website to try to raise funds to help find the sisters and had so far collected more than $7500. The funds will now be donated to charity.
The women vanished about January 11 after travelling to Mendoza to visit Gilad, who had been living in Argentina for more than 10 years.
Childhood friend Eti Krief Haimi said she was in daily contact with Ms Pereg via a WhatsApp group chat called "friendship forever".
"The last message you sent to us on 11/1/19 hour 23.06 was: "wishing you a peaceful Shabbat.. Shabbat shalom dear girls.." with full of hearts and flowers," she posted on Facebook.
"You stopped responding to us, it was a little weird, but we thought you were on a flight somewhere."
She paid tribute to Ms Pereg's "big smile" and love of life and travel.
"You left a huge hole with us. We didn't dream in the worst deal we'd have to break up with you so fast."
Autopsy results showed at least one of the women was shot. Local media are reporting the victim had suffered three gunshot wounds while the other showed signs of having been dragged.
Gilad Pereg, who reportedly was the Argentine chairman of five companies set up by his mother, has now been transferred to a local prison.
The Department of Foreign Affairs and Trade on Monday confirmed it was providing consular assistance to the family of an Australian woman who died in Argentina.
"Owing to our privacy obligations we will not provide further comment," a spokeswoman said.
The university on Monday released a statement saying the community was shocked and saddened by the professor's death "while holidaying in Mendoza", and expressed heartfelt condolences to all of those affected.
Dr Pereg was a microbial ecologist with 25 years experience as a researcher in plant and social microbiology.
She obtained a PhD from the University of Sydney in 1998 and later worked for the Institute for Genetics at the University of Cologne in Germany before joining UNE in 2001.
"(Dr Pereg) was held in high esteem by her colleagues and students as a committed and dedicated academic," the statement reads.
"She was acknowledged nationally and internationally as a leading scholar in the fields of soil microbial ecology and plant-microbial interactions."
Australian Associated Press