While the family of western Sydney woman Cheryl Ardler know in their hearts she is dead, they want closure and will join NSW Police in announcing a reward for information into the suspected murder nearly six years ago.
The 41-year-old was last seen by neighbours near her Cranebrook home in the days leading up to Christmas in 2012, and human remains located in nearby bushland in May this year confirmed the bones belong to Ms Ardler.
In 2016, a coroner found that she died sometime between December 5-25, 2012 and the manner of her death was most likely to have been homicide.
"We know that somebody has killed her," Ms Ardler's sister Margaret said at the time.
"She hasn't just done a runner or gone walkabout."
The woman's grief-stricken mother said she knows her daughter is dead.
"Part of me didn't want to believe it," mother Irene Ardler told AAP at the NSW Coroners Court in 2016.
The case was then referred to the Unsolved Homicide Squad.
Ms Ardler's mother and sisters will join Homicide Squad Commander Detective Superintendent Scott Cook on Thursday in announcing the NSW Government's reward which has been upped to $750,000.