A fitness tracker pinpoints the exact moment Thomas Bednar broke into his mother's home and killed her.
He had long held ill feelings toward 78-year-old Judy Bednar and it grew in intensity in the lead-up to his murderous attack on her in May 2021.
It was planned and vicious, and followed a campaign of conduct designed by him to harass her, motivated by his belief she had caused him to be hospitalised for mental health conditions in the year prior.
Bednar, 54, was jailed on Tuesday for 29 years by Victorian Supreme Court Justice Andrew Tinney.
Ms Bednar's badly beaten and naked body was discovered in the bedroom of her Chelsea home days later when she could not be contacted by friends.
For the months before her death she lived in entirely well-founded fear of her son, and one could only imagine the terror she felt waking up to discover him in her home, Justice Tinney said.
The attack he committed was of "scarcely believable ferocity", he said.
She suffered severe blunt force injuries and a number of possible causes of death were identified or could not be excluded, including strangulation or suffocation.
Her Fitbit had recorded her going to sleep just after 2am on May 14 and at 4.47am recorded her waking with a sharp bust of activity.
Then, nothing. Her broken Fitbit was found near her body.
Justice Tinney said Bednar immediately demonstrated a lack of remorse and regret, which continues now.
He has repeatedly maintained his innocence and argued at trial it was family friend Danny Cohen who killed his mother.
Justice Tinney said that showed a level of desperation and vindictiveness in Bednar.
He blamed his mother for a series of involuntary mental health admissions and at a family meeting read a list of grievances against her, including that she never took him to soccer practice as a child.
Mrs Bednar had taken out an intervention order against her son, fearing he would hurt her. He had been engaged in petty acts including turning off her power.
She told friends she feared for her life but police had said they couldn't do anything unless he physically harmed her.
"By that time it'll be too late, because I'll already be dead," she told her friends.
Justice Tinney was not positive about Bednar's prospects for rehabilitation.
He said he had given every indication he was a resentful and embittered man who had added the criminal justice system to the list of those he believes have wronged him.
Bednar, who has already spent nearly two years behind bars, must serve at least 23 years before he's eligible for parole.
