Brothers Gary Anderson (25) and Sean Anderson (23) both of Grafton Street and Michael Dunlop (21) of Fern Park in Derry are all charged with the murder of Karol Kelly in Derry on March 4, 2018.
Dunlop is further charged with attempting to cause grievous bodily harm with intent on Mr Kelly and doing an act with intent to pervert the course of justice on the same date by attempting to conceal knives on the same date.
The woman who lived in Grafton Street at the time of the incident said her partner said to her he heard there was a fight and she had looked out the window.
She told the jury that she saw one man running and two people 'chasing in close proximity.'
The witness said that the man being chased fell and then picked himself up and ran on down the street.
The woman said that a short time later she saw a man walking back up the street who seemed 'quite calm.'
The court was told that the witness saw a woman in her pyjamas speaking to the man about killing and he made his reply.
The woman said she called an ambulance.
The trial continues.