The post-mortem examination for rap star ODB (Ol'Dirty Bastard) could take up to a week to be completed, US officials have said.
ODB's most famous song was Got Your Money
The 35-year-old collapsed and died at a Manhattan recording studio on Sunday after complaining of chest pains.
The rapper, whose best-known song was Got Your Money, was dead before paramedics could reach him.
ODB, who would have been 36 years old on Monday, was a founding member of the Wu-Tang Clan in the early 1990s.
While the cause of death is not clear, in 2001 ODB completed a jail sentence for possessing drugs.
The prison term was also imposed on the rap artist for escaping a rehabilitation clinic.
After working with the Wu-Tang Clan, ODB released several singles which were hits in the US, and worked with a variety of artists including Mariah
Got Your Money, which featured Kelis, was a hit in the UK back in 2000.
Over the years he was involved in several shootings and was arrested on a variety of charges, including shoplifting, drug offences and threatening a former girlfriend.
He had been working on a comeback album, which was nearly finished when he died.
His mother, Cherry Jones, said: "To the public he was known as Old Dirty Bastard, but to me he was known as Rusty. The kindest most generous soul on earth."
ODB joins a string of rap stars who have met untimely deaths, including Tupac Shakur,who was shot dead in 1996.