An autopsy carried out Monday did not establish what killed 27-year-old singer Amy Winehouse.
The Metropolitan Police said further tests, including toxicology tests, would be carried out. The results are not expected for between two and four weeks, the AP reports.
An inquest into the death was opened and adjourned Monday to allow the Winehouse family time to make funeral arrangements and a private service could take place as early as Tuesday.
A full inquest hearing has been scheduled for October.
Her family says it "has been left bereft by the loss of Amy". Fans have left flowers, cigarettes and alcohol outside the singer's north London home in tribute to the late star and her parents Mitch and Janis Winehouse thanked people for their support.
Meanwhile, Microsoft has apologized for a Twitter message it sent out encouraging people to "remember Amy Winehouse" by downloading her Back to Black album via the company's music service Zune.
However, Microsoft's message did not go down well this morning, with comments in response ranging from, "Slick move, Bill & Steve" to "crass much?".
Although the original message was not deleted, Microsoft's UK PR account (@tweetbox360) later sent a message saying:
Apologies to everyone if our earlier Amy Winehouse ‘download’ tweet seemed purely commercially motivated. Far from the case, we assure you.
The 27-year-old singer's death sparked a spike in sales of her debut album, with sales increased some 37 times between Friday and Saturday.
(More in Global Post Breaking News: Amy Winehouse found dead at London home)