Police are investigating whether a woman who died from severe head injuries after a violent attack at her house was followed home.
Laila Rezk returned home from work on the number 85 bus
Laila Rezk, 51, was found unconscious after she had returned from work to her home in Robin Hood Lane, Kingston Vale, south west London, on Wednesday.
Police said Mrs Rezk may have opened the door to her attacker, as there was no sign of a forced entry.
CCTV footage of her on a bus has been released in an appeal for witnesses.
Det Supt Richard Heselden, who is leading the murder inquiry said it was a "very violent and nasty" attack.
Police officers are investigating whether someone followed Mrs Rezk home and then attacked her.
"What we do know is that there was no obvious sign of forced entry, so it is possible that Laila opened the door to her attacker," he said.
He said Mrs Rezk's son, daughter and her daughter's boyfriend arrived at the house in the evening and found the front door slightly ajar.
They found Mrs Rezk lying between the living room and hall.
Miss Rezk's boyfriend tried to resuscitate her before she was taken to St George's Hospital in south London, where she died the next day.
A post-mortem examination concluded she died of severe head injuries.
Laila Rezk was attacked at her London home
Mrs Rezk boarded a number 85 bus at Putney railway station at 1920 GMT and got off in the vicinity of Robin Hood roundabout, near Robin Hood Lane, about 20 minutes later.
Police have released CCTV footage from the bus taken at about 1930 GMT.
Det Supt Richard Heselden said the police wanted to hear from anyone who may have been on the bus and remembered seeing Laila.
"She was wearing a full-length dark brown leather coat, dark coloured boots and she was carrying a large beige handbag with handles, and a plastic carrier bag which we believe was purple and white.
"Laila was slim and had dark brown shoulder-length hair."
No arrests have been made so far.
An inquest is due to be opened and adjourned next week.