A post-mortem examination into the death of law firm accounts manager Sally Hodkin has confirmed she died after suffering knife wounds to her neck.
The victim was believed to be on her way to work on Monday morning when she was attacked in a busy shopping street in Bexleyheath, south east London.
A woman accused of her murder had been due to appear in court on Tuesday but was unable to because of "extreme" mental health problems.
Unemployed Nicola Edgington, 31, of Ambedkar House, Flavell Mews, Greenwich, south east London, was also charged with the attempted murder of 23-year-old Kerry Clark, who was attacked with a knife as she waited at a bus stop.
A psychiatrist said Edgington was unfit to be taken into the courtroom to face charges.
Addressing Greenwich Magistrates' Court, Dr Amit Chatterjee said: "I had the opportunity to meet her this morning. She does have extreme mental health problems. I don't think she is fit to attend court in her mental state."
A Serco security guard summoned to describe Edgington's condition said the woman was "agitated".
Lisa Moriarty told the court: "At the moment she is in a cell with three officers but I am a bit reluctant to bring her up with everyone around. She seems to be very agitated with people in the cells, she's getting very agitated and uppity."
Edgington, who was represented by her solicitor, Callum Haddow, was told her case will be heard next at the Old Bailey on Thursday when a bail application is due to take place. A plea and case management hearing was scheduled for January 17.
Oxleas NHS Foundation Trust, which provides mental health services in a number of south east London boroughs, said Edgington had unexpectedly left an assessment suite while a bed was being prepared for her at 7am on Monday.