Police have announced a $1 million reward for information about the death of a woman at Healesville, north-east of Melbourne, almost 20 years ago.
Marea Yann, 69, was found dead in her home on September 30, 2003.
Her body was found in an armchair in her lounge room and she had suffered extensive head and upper body injuries.
Detectives said the TV in the house was left on and there was no sign of forced entry into the house.
Marea's purse was found on the floor but nothing appeared to have been taken from the property.
A then-46-year-old man, who was known to Marea, was charged with her murder in 2006 but he was acquitted at a trial in 2008.
A $100,000 reward was offered in 2005 but that has been increased to $1 million in the hope that it provides new leads for detectives who recently revisited the investigation.
Marea's son Jeff Yann said his mother was a much-loved and respected member of the Healesville community.
"Mum was the quintessential loving mother, nonna and friend. Mum was a shining light in the Healesville community. She worked tirelessly volunteering her time at the local op shop and charities," he said.
"She was taken from us in such a brutal, violent manner that we could never let this thing go and mum deserves justice."
Mr Yann believes someone may know who killed his mother in 2003 and why.
"I would hope that this would remind them of the incident that happened and for those people who might be timid or afraid to come forward, perhaps the incentive's there with a million dollars to feel confident they can come forward with information," he said.
"This person who committed such a cowardly and brutal act has been walking freely in the community for 20 years."
Detective Superintendent Janet Stevenson from Victoria Police Crime Command urged anyone who may know anything about Marea's death to come forward.
"Marea was a much-loved sister, mother and grandmother and we know her family still feel her loss as keenly as they did almost 20 years ago," she said.
"She was a vulnerable older woman who was brutally murdered in the place she should have felt safest."
Detectives have spoken to dozens of people in the initial investigation and the revisiting of the case and are hopeful it can still be solved.
"Hopefully this public appeal provides the motivation for someone to contact police after all these years, who can help us solve Marea's murder," Detective Superintendent Stevenson said.
"Time and time again it has been proven that even the smallest piece of information can make the biggest difference when it comes to solving a crime."
Anyone who has information can contact CrimeStoppers on 1800 333 000.
