A man has claimed "that's just what happens when you're a heroin addict" after admitting his role in the death of his long-term partner.
Christopher Roy Weaver, 40, pleaded guilty on Wednesday to multiple charges, including manslaughter and administering a declared substance without authorisation.
"Um, yeah, guilty," he said via audio-visual link from the Alexander Maconochie Centre after special magistrate Sean Richter read out the charge of manslaughter.
"It was all an accident but yeah, guilty."
Police arrested Weaver in July, almost two years after he injected partner Laura Crncevic with the shot of heroin that would kill her.
The pair were celebrating their seven-year anniversary on the night of August 19, 2021, at their Florey home.
Ms Crncevic collapsed and vomited 20 seconds after being injected with the lethal dose.
The offender called emergency services and began CPR at their instruction.
"Come back to me, come back to me. Don't die," Weaver yelled while paramedics worked on the woman.
Resuscitation efforts were continued in the ambulance, and at Northside Canberra Hospital, but Ms Crncevic was pronounced dead about two hours after the injection.
On Wednesday, Weaver also pleaded guilty to resisting a territory public official, damaging a police vehicle, failing to stop a motor vehicle for police and failing to appear after a bail undertaking.
Those charges relate to Weaver ramming a police car in an effort to help a woman escape officers in March of this year.
"I slept in that day. Guilty," Weaver responded to the failing to appear charge.
The court previously heard how Weaver had made an "overwhelming number" of admissions, detailed in court documents, to several civilians and police about his role in killing Ms Crncevic.
"She asked me to inject her and I was really high and f----- her dose up ... try living with that guilt," the man said in one message.
"I feel like a f---ing murderer," he said to a woman over the phone.
"I accidentally overdosed her. It's my fault. Totally my fault," he wrote to another person.
Weaver, a heavy heroin user, described himself to police as a "junkie".
While the offender needed a injection of the drug every 12 hours, police documents state the victim usually only used on weekends.
Weaver's two charges relating to the death of his partner were committed to the Supreme Court.
Before being disconnected, Weaver gave the court two thumbs up after his lawyer said he would be in contact before the offender's next court appearance.
Weaver is next set to appear later this month.
