Argentinian police investigating the death of Australian-born university professor Lily Pereg say they found spots of blood on a bag at her nephew's home, as well as a cut security camera cable.
Dr Pereg, 54, and her sister, 63-year-old Israeli citizen Pyrhia Sarusi, were last heard from on January 11.
The two were visiting Ms Sarusi's son, Gilard Pereg, near the city of Mendoza.
Their bodies were found on a lot beside the 36-year-old's home and he has since been arrested on homicide charges.
According to local media reports, several registered guns were found at Mr Pereg's property along with some dissected cats.
Prosecutor Claudia Rios said there was security vision in front of the property showing the two missing women entering with him.
"We don't have vision of them leaving the property," she said.
Ms Rios said the camera's cables had been cut.
"We found some spots of blood on a bag of cement at the back of his property and we matched that with the DNA from the toothbrush of the missing women."
Speaking prior to his arrest last week, Mr Pereg said the head of the investigation came to his house, but he was not initially detained.
"It's clear they haven't found anything illegal in my house," he said.
Mr Pereg said he wanted to leave Mendoza if he could sell his property.
Autopsy results found at least one of the two women had been shot.
Dr Pereg was a microbial ecologist at the University of New England with 25 years of research experience in plant and soil microbiology.
Colleagues and students have paid tribute to the researcher, describing her as compassionate and a respected scientist.
A GoFundMe page set up to raise money to search for the women included a message from her family expressing shock at the alleged murder.
"There will never be an explanation," it said.
