An inquest, which recorded an open verdict, heard that he died of inhaling vomit after taking nine barbiturates and passing out. Since his death there have been rumours that Hendrix's life could have been saved if an ambulance had arrived earlier. There have also been apparent discrepancies over the time of death.
The new investigation has been ordered by the Attorney General, Sir Nicholas Lyell, in response to an approach by Kathy Etchingham, a former girlfriend of Hendrix, who says she has fresh information about his death. Sir Nicholas will examine any new evidence before deciding whether to give consent for an inquest being reopened, with the High Court making the final decision.
Ms Etchingham has claimed: 'The death was all very dodgy. I don't think it should have happened. He was in the wrong place at the wrong time with the wrong people.'
Noel Redding, a former bass player with Hendrix's band, the Jimi Hendrix Experience, speaking yesterday on BBC Radio 4 said: 'The supposition is now that he died much earlier than supposed and that someone tried to cover it up.'
Miss Dannemann, 48, who lives at Seaford, Sussex, said yesterday that she was relieved that the investigation had been re-opened. 'For the last few years people have made allegations that I didn't take enough care of Jimi and that he died hours before I said he did. If there's a police investigation they will find out that what I said at the inquest is true.'
She told the inquest in September 1970 that on the night of Hendrix's death they had drunk some wine. Miss Dannemann said when she woke up on the morning he died it was not immediately obvious that anything was wrong with the guitarist. 'He was still sleeping, and so I got my breakfast and had a wash, and went to get some cigarettes because we had run out. When I came back he was still sleeping. I looked at him closely and then I could see something was wrong.'
She said she then tried to contact Hendrix's doctor before telephoning for an ambulance. The inquiry will be headed by Det Supt Douglas Campbell, of Scotland Yard's International and Organised Crimes Branch.
Hendrix, who was born in Seattle, is considered by many to be the greatest ever rock guitarist. He was famous for playing his instrument behind his back and with his teeth.