A post mortem examination is carried on the funk star...

A post mortem examination has failed to determine the cause of funk legend [/a]’s death.

The star died in his sleep on Friday (August 6) at the age of 56.

David Smith, investigator at the Los Angeles coroner’s office, told the Associated Press agency they were awaiting results of a toxicology test.

He added that it could be several weeks before the results are known.

[a]’ three children, daughter Ty and sons Rick Jr and Tazman said that they believe their father died of heart failure.

As previously reported on NME.COM, a statement was issued, which read: “Rick James passed away this morning (August 6) at 9:20 AM in his sleep of natural causes at his Los Angeles home.”

The singer was most famous for his hit ’Superfreak’ and throughout his career he received numerous Grammy nominations and sold millions of records. However, his personal life was more troubled. The star spent time in jail for assault, and had a documented history of drug problems.

Details on the funeral will be announced shortly.