A post-mortem examination into the cause of George Michael’s death was “inconclusive” police have said.
The star died aged 53 on Christmas Day at his home in Goring-on-Thames, Oxfordshire.
More tests will now be carried out to determine what led to his death, Thames Valley Police said in a statement. The results of these tests are unlikely to be known for several weeks.
Michael’s death is still being treated as unexplained but not suspicious.
The post-mortem examination took place on Thursday.
South Central Ambulance Service were called to Michael’s property at 13:42 GMT on 25 December and the singer was confirmed dead at the scene. Thames Valley Police also attended.
Michael’s manager, Michael Lippman, said he had died of heart failure.
Michael, who was born Georgios Kyriacos Panayiotou in north London, sold more than 100 million albums throughout a career spanning almost four decades.
He first found fame with schoolfriend Andrew Ridgeley in duo Wham! in the 1980s – reaching number one in the UK singles charts on four occasions – before forging a successful career as a solo artist.