Anna Horneshaw was 27 years old, 20 weeks pregnant and desperate for a cigarette one Saturday night when she grabbed a boning knife belonging to her housemate and stabbed him at least 20 times.
Although she initially told police the culprit was an intruder who threatened to cut her baby out of her, Horneshaw pleaded guilty on Friday to what her own lawyer described as an "outrageous and aggressive" murder of 67-year-old Zvonimir Petrovski.
The Victorian Supreme Court heard she asked Mr Petrovski, who was drinking in the loungeroom of their Thomastown home with the father of her child Grant Brennan, for money to buy cigarettes.
Crown prosecutor Susan Borg said the man eventually took out a couple of notes, which she snatched out of his hand.
Mr Petrovski followed her into the kitchen, asking for it back but she punched him sending him crashing into a wall.
Suffering withdrawals from nicotine, cannabis and alcohol and starving because of severe morning sickness, Horneshaw then grabbed the knife and plunged it multiple times into his back and neck.
Mr Brennan screamed at her to stop and he called triple-zero.
The killer later said her actions "did not feel real and she could not believe how fragile he was".
Horneshaw took over the triple-zero call while Mr Brennan pulled the knife out of Mr Petrovski's back.
She cried on the phone that "someone stabbed my Daddy", Ms Borg said.
In the hours afterwards, Horneshaw and Mr Brennan gave inconsistent statements to police alleging their housemate had been attacked by an "unknown intruder" who, she claimed yelled : "Is that bitch pregnant? I'll cut the baby out of her".
Mr Brennan later gave a true account to police and was released without charge.
A "conglomeration of stresses" had brought Horneshaw, who had no previous criminal record, to a "tipping point", lawyer Scott Johns said.
Horneshaw, who had discovered she was pregnant quite late, had been consuming 35 to 40 alcoholic drinks a day and smoking cannabis.
She was living in a messy home with two chronic alcoholics in Mr Brennan and Mr Petrovski, five cats and little food.
As a child she had gone from being a "much loved little girl" to being the victim of "extreme" bullying at school.
Three childrens' books co-authored with her mother touched on her experiences: "Two Weeks in Grade Six, A Term in Year 7 and Escape from Year 8".
Horneshaw has suffered mental illness, an eating disorder, post-traumatic stress after a sexual assault, attempted suicide and abused drugs and alcohol, Mr Johns said.
At the time of the murder she had stopped taking her anti-psychotic medication.
On Friday morning Horneshaw submitted a letter to Justice Dixon, detailing her "deepest sorrow and horror" and what she had done to her housemate and friend.
Horneshaw, now 28, gave birth in April last year but only had custody of her child for 24 hours.
Friends and family of both Mr Petrovski and Horneshaw attended the court.
She will be sentenced at a later date.
Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14. Suicide Call Back Service 1300 659 467.
