The battered body of an elderly woman was found partially covered in newspapers, shopping bags and pillows on the floor of her unit in Sydney's northern beaches, a court has heard.
Marita Therese Cunningham, 50, has pleaded not guilty to murdering her ex-fiance's 81-year-old neighbour May Ritchie at Freshwater on March 20 last year.
She's accused of assaulting Ms Ritchie with "either her hands or a walking stick" then strangling her to death, crown prosecutor Craig Patrick SC said in his opening address at the NSW Supreme Court on Monday.
As she walked away from the scene, a police officer asked "What is with all the blood on your shirt?"
"I've got my period," she allegedly replied.
Cunningham's barrister Belinda Rigg SC said Cunningham's acts did cause the death of Ms Ritchie but she "did not know what she was doing was morally wrong".
"She was suffering from a schizoaffective disorder at the time she committed these acts," Ms Rigg said in her opening address.
The court heard Cunningham's mental health deteriorated in the weeks leading up to Ms Ritchie's death.
She was allegedly seen "acting like a cheerleader" on her street, lifting her top and skirt up to expose herself as cars drove past.
She allegedly hit a neighbour's car with a cricket bat, and complained to responding police of having a possum stuck in her roof.
Cunningham was previously engaged to Ms Ritchie's neighbour Bob Lyford, who had taken out an AVO against her after their relationship deteriorated, Mr Patrick said.
On the afternoon of the alleged murder, Cunningham turned up at Mr Lyford's house to watch football, saying the AVO had expired.
"F*** off I never want to see you again," Mr Lyford allegedly told her.
Instead, Cunningham went across the road to drink and socialise with Ms Ritchie.
Hours later Mr Lyford went to check on his elderly neighbour. He saw the accused standing in the lounge room but no sign of Ms Ritchie.
He soon found Ms Ritchie lying on her back under some newspapers on the floor, with blood on her face and lumps on her forehead, Mr Patrick said.
An autopsy found she died from asphyxiation, had blunt force injuries to her face and scalp, and defence-type injuries on hands.
Cunningham appeared "confused," "slurring her speech" and "talking about possums in her roof" at the police station after her arrest, Mr Patrick said.
When officers told her of the charges, she allegedly replied "What, she's dead?"
The judge-alone trial continues before Justice Robert Beech-Jones.