But a handwritten letter from Billings tendered to the NSW Supreme Court opens with his own misery, having spent almost two-and-a-half years in the notorious supermax wing at Goulburn jail.
The 31-year-old has pleaded guilty to murdering his ex-girlfriend in a frenzied stabbing after breaking into her bedroom at her Forbes home, in the state's central west, just before midnight on April 21, 2024.
He had been released on bail by a local court registrar a fortnight before the attack, charged with a series of sexual assault and domestic violence offences against Ms Ticehurst.
As soon as he learned of her allegations of repeated rapes, Billings adamantly denied the crimes and developed a twisted obsession with clearing his name.
The murder was a form of retribution, according to prosecutors' submissions.
The court has also been told Billings was hung up on his perceived mistreatment by police, who he said disrespected him by throwing a Queensland boxing singlet in the dirt.
In the letter presented to the court as part of Billings' sentence proceedings, the former mine worker began by describing being "messed up" for some time before the murder.
"I didn't think life could be much worse, then over a period of a week it got a lot worse," Billings wrote.
"In them few weeks (sic) I went from a hard working average person to accused monster and police treated me as such.
"Then I can't even comprehend what happened next ... I took a person's life from this world and in doing so I ruined many more."
Billings wrote of being locked in a "tiny concrete room you can't escape", which reminded him of the crime every morning.
Though he wrote he couldn't bring Ms Ticehurst back, he could take responsibility for his actions.
"I'm not a heartless monster like they say," he said.
"I'm just a human, capable of making mistakes and capable of feelings and emotions and I feel like absolute shit and I'm as sorry as a person can be for what I have done."
Prison records tendered by the defence showed Billings works as a sweeper in the supermax wing.
Billings described himself as a "loner" outside jail, who coped better on his own, the prison document said.
A letter from a Catholic chaplain said Billings had made a "profound change" in jail, taking a spiritual journey from a dark place.
However the chaplain's October 2025 letter suggested Billings was still focused on his claims of being wrongly accused of sexual assault.
"Dan lives with unanswered questions of 'why the person I trusted betrayed me and made false accusations against me and what snapped within me'," the chaplain's letter said.
"He accepts the consequences of his actions and ponders how, with the grace of God, he can turn this profound tragedy into something positive."
Billings will face the second day of the sentence hearing on Friday.
The court heard victim impact statements from Ms Ticehurst's family early on Thursday.
"When she died, part of me died with her," her father Tony Ticehurst said, his voice heavy with emotion.
Ms Ticehurst's mother Kate's statement was read aloud by a relative.
"Molly was my only child and my best friend," her statement said.
"I'm heartbroken that my girl is no longer with me."
Justice Natalie Adams has indicated she will sentence Billings later in September.
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