Amy Winehouse spent her last night alive on Friday watching videos and playing drums for two hours in the bedroom of her £2m mansion in Camden, north London, prompting neighbours to complain about the noise under the false impression that she was hosting a party.
Winehouse's security guard is expected to tell police that the singer spent Friday evening alone.
On Saturday morning the guard checked on a sleeping Winehouse and saw nothing out of the ordinary.
Later the same day, he returned and discovered she had stopped breathing.
He immediately reported the situation to the emergency services who rushed to the scene, along with Winehouse's on-off boyfriend Reg Traviss, who was later seen in "extreme distress" in the street.
A day after her sudden death at the age of 27, large crowds remained outside her house – a mixture of friends, passers-by, devoted fans and a smattering of tourists.
"I didn't sleep last night," wailed Matthew Rile, 32, an unemployed man from Deptford with a large Amy Winehouse tattoo on his calf.
Winehouse's family await the result of a post-mortem examination, which is expected to be delivered either today or tomorrow.
Yesterday, her mother Janis said she believed her daughter's death was "only a matter of time" when they met on Friday. "She seemed out of it," she said. "But her passing so suddenly still hasn't hit me."
Winehouse's family said in a statement they had "been left bereft by the loss of Amy, a wonderful daughter, sister, niece.She leaves a gaping hole in our lives. We are coming together to remember her and we would appreciate some privacy and space at this terrible time."
Russell Brand, a friend of the singer, said: "She wasn't just... another p****d-up nit who was never gonna make it, nor was she even a ten-a-penny-chanteuse enjoying her 15 minutes. She was a f**king genius."