A woman fatally slashed her film director sister in the neck and snatched her diamond-encrusted gold Rolex watch, a court has heard.
Nancy Pexton, 69, is accused of killing her older sibling, Jennifer Abbott, at her flat in Camden, north London, on June 10 last year.
Three days later, a neighbour forced open Ms Abbott's door after becoming concerned he could not hear her corgi dog Prince barking.
Ms Abbott's body was found on her living room floor with a wound to her neck and gaffer tape over her mouth.
She was not wearing her Rolex watch which she was "greatly attached to" and never usually took off, jurors were told.
Pexton, of no fixed address, is on trial at the Old Bailey accused of murdering Ms Abbott.
Opening the case on Thursday, prosecutor Bill Boyce KC said there was no evidence that Ms Abbott was alive after Pexton visited her on June 10.
The sisters had spoken by phone at 11.36am with Pexton travelling by bus to her flat at 12.45pm and staying for an hour.
After allegedly killing her 69-year-old sister, Pexton called her GP and said she had taken an overdose, Mr Boyce said.
She was taken to hospital by ambulance where she stayed before her arrest on June 18, jurors were told.
Mr Boyce told jurors: "She said she could not remember what had happened in the previous 90 minutes, which was the period we say she was undoubtedly in her sister's flat, the period we say she murdered her sister."
Jurors heard that Ms Abbott's body was found at her Mornington Place flat on the afternoon of June 13.
The victim's niece, Mai Pexton, had gone to the property and banged on the door, screaming for her "auntie".
A neighbour decided to break down the door because he could not hear Ms Abbott's corgi dog Prince barking, which he found unusual, the court heard.
He called emergency services after discovering Ms Abbott's partially naked and decomposing body on the floor.
She had a large, gaping "slash-type" wound across her neck and gaffer tape across her mouth, jurors heard.
Ms Abbott's corgi had been locked in the bathroom and was freed by firefighters, Mr Boyce said.
The prosecutor told jurors: "It was in desperate need of a lavatory but was fed and watered and given to Mai to take away in good health."
He told the court Ms Abbott usually wore her Cartier bracelet and gold diamond encrusted Rolex watch which was of "real sentimental value".
The watch that Ms Abbott "never took off" and was "greatly attached" to was later discovered when police searched Pexton's bag, Mr Boyce said.
The defendant allegedly responded: "Oh yes, that's my sister's. She asked me to look after it."
A post-mortem examination found Ms Abbott had sustained a number of stab and slash wounds and a single defensive wound to the right hand.
The defendant, who was nine months younger than the victim and turns 70 on Friday, was effectively homeless and had been staying near Baker Street.
Mr Boyce said the central issue in the case was whether Pexton, who has two adult daughters, was responsible for killing her sister.
She has denied murder and the Old Bailey trial continues.
