An autopsy on singer Amy Winehouse Monday

LONDON — An autopsy on singer Amy Winehouse Monday failed to determine what killed the 27-year-old star, leaving fans and family with a weeks-long wait for the results of toxicology tests.

Winehouse's devastated parents visited mourners outside her north London home to thank them for their support, ahead of a private family funeral that could be held as early as Tuesday.

The singer, who had struggled with drug and alcohol abuse for years, was found dead Saturday at home by a member of her security team, who called an ambulance. It arrived too late to save her.

The Metropolitan Police said Monday that a forensic post mortem "did not establish a formal cause of death and we await the results of further toxicology tests." Those are expected to take two to four weeks.

An inquest into the singer's death was opened and adjourned at London's St. Pancras Coroner's Court. During the two-minute hearing, an official read out the name, birth date and address of Winehouse, described as "a divorced lady living at Camden Square NW1."

"She was a singer songwriter at the time of her death and was identified by her family here at St. Pancras this morning," said coroner's officer Sharon Duff.

Duff said the scene of Winehouse's death "was investigated by police and determined non-suspicious."

In Britain, inquests are held to establish the facts whenever someone dies violently or in unexplained circumstances. Assistant Deputy Coroner Suzanne Greenaway said Winehouse's inquest would resume on Oct. 26.