"I will stab you and cut your head off with a knife" was the repeated threat a woman made to strangers over the phone before decapitating her mother, a Sydney jury has been told.
Matthew Layfield owned a meat business in 2019 when he and his employees "were relentlessly targeted" by Jessica Camilleri making hundreds of calls a day to each of their mobile phones.
The phone conversation between Camilleri and whoever she was speaking to would "turn ugly" when they tried to end the call.
Detective Sergeant Grant Gilbert read out Mr Layfield's statement to the NSW Supreme Court on Thursday about the ongoing harassment which lasted two months.
"I will stab you and cut your head off with a knife. It always ended like that, it did not matter who she was talking to," the statement read.
Camilleri, 27, has pleaded not guilty to murdering her mother at their St Clair home in Sydney's west in July 2019.
Both the prosecutor and defence barrister agree Camilleri stabbed her 57-year-old mother, her sole carer
The jury must decide whether the charge can be reduced to manslaughter with the partial defence of being unable to control her actions due to a substantial impairment of the mind.
The horror movie fan stabbed her mother more than 100 times before her head was found on the footpath outside and her decapitated body on the kitchen floor, the court has heard.
Mr Layfield recalled the first "scattered call" to his employee along the lines of: "You're going to die of f***ing cancer if not I will stab you until you die you mother f***er".
The response was "that's lovely thank you ... and ended the call".
Mr Layfield soon made regular contact with her mother and sole carer who said her daughter had developed a huge crush on him after seeing his photograph on the company's website.
After Mr Layfield's friends and family members were also targeted he became increasingly frustrated and told Rita Camilleri "something needed to happen".
The 57-year-old then burst into tears saying she was at her wit's end and did not know how to control her daughter anymore.
Det Sgt Gilbert found eight copies of the Texas Chainsaw Massacre and five of Jeepers Creepers following a search of the home.
On Thursday family friend Jade Arena was recalled for re-examination about her evidence that she was afraid for Rita Camilleri's safety and said she may be murdered.
Ms Arena "definitely" remembers the conversation where Ms Camilleri spoke of her "soft" daughter who "wouldn't hurt a fly".
She described Jessica Camilleri's fixation on not being placed into a mental health facility and how she would "rather kill somebody" than be sent back to such a place.
Camilleri had suffered social, behavioural and learning difficulties including ADHD since she was a child, and was later diagnosed with conditions including anxiety, rage disorder and autism spectrum disorder, the court has heard.
The trial continues.
