Fighting back tears, she told Crown prosecutor Ben Vanderkolk her grandma had described one of the teens in vivid detail.
"She said 'that young girl had pure evil in her eyes'," she said.
Virtue's daughter-in-law, Jennifer Virtue, had known the victim for decades.
She said the 90-year-old called a spade a spade and loved her family to bits.
"She was a beautiful caring woman who loved nature and loved her family," she said.
Jennifer Virtue said her mother-in-law had a bright outlook and a huge compassion for others.
One of the accused is 14 years old and is expected to have her 15th birthday during the trial.
Her lawyer, Mike Antunovic, told the jury in his opening remarks his client had got cold feet moments before the home invasion and wanted to pull out.
"Today here standing trial for murder she is of the same age - 14 - she's still 14 years old members of the jury," he said.
Other defence lawyers reminded the jury to keep an open mind when hearing evidence.
Justice Cull also reminded them to put emotions aside because some of the evidence may be "distressing and distasteful".
Crown prosecutor Ben Vanderkolk told the court the teenagers' main goal was to get money - they had targeted Virtue's home because she was elderly and lived alone.
"The three young women wanted and needed money - they had identified a house - it had a vulnerable occupant ... they were armed with at least one or two lethal weapons," he said.
He said two of them went inside while a third was on the lookout outside.
He said Virtue was assaulted and her handbag was taken.
"Mrs Virtue's debit card was then used to buy three Chupa Chups, drinks, a hoodie, a pair of jeans and tobacco.
"The card declined on attempted purchases of more cigarettes and alcohol," he said.
More than 50 people were expected to give evidence and the jury trial could last up to three weeks.
