A woman with the "propensity to be violent" murdered her friend by pushing her down the stairs, a jury heard.
Linda Rainey, 60, died two days after suffering a head injury at a flat in South Market Road, Great Yarmouth, Norfolk, on 5 August 2019.
In his closing speech, prosecutor Andrew Jackson QC said Rosalind Gray, 55, "deliberately" pushed Ms Rainey.
Ms Gray, of Marlborough Square in Yarmouth, denies murder at her trial at Norwich Crown Court.
The owner of the flat, Adrian Lawrence, 55, of South Market Road, Great Yarmouth, has pleaded not guilty to conspiracy to pervert the course of justice.
Ms Gray has also denied the same conspiracy charge.
Mr Jackson claimed Ms Gray had the "propensity to be violent without regard for human life".
"Ms Gray deliberately pushed Linda Rainey down the stairs knowing at the very least she intended to cause really serious harm," he told the court.
Mr Jackson said Ms Gray "showed barely a flicker of emotion" on hearing of Ms Rainey's death.
Earlier in the trial, the prosecution said the pair had discussed going on holiday together and texts revealed a dispute over £200 allegedly owed to the deceased.
During his closing speech, defence barrister Gregory Bull QC said despite being "best friends" there had been some "bad blood and animosity".
He said the death was "tragic", but an "accident".
"This is not a case of murder, it's all about an alleged push at the top of the stairs by two one-time friends," he said.
He added it was dark in the flat and the incident happened "in a flash".
The trial and closing speeches continue.