In the three decades since the death of Elvis Presley in a Graceland bathroom spawned a generation of conspiracy theorists, legions of supposed love children have made claims on the King.

The majority have quickly been exposed as scams, hoaxes or the delusions of obsessed fans. Never before has a court found sufficient evidence to reopen the music legend's estate, as a Tennessee judge has now ordered, in the bizarre case of a Memphis woman claiming to be half-sister to The King - who, she says, is very much alive.

Eliza A Presley - an adopted name - says she has DNA evidence that the rock 'n' roll legend lives on, and that they share the same father. Faced with the refusal of Elvis's closest living relative, his daughter Lisa Marie, to provide a DNA sample, she has launched a lawsuit to force her claim to be examined. Her success so far is the talk of a city which has never quite got over the loss of its favourite son.

The roots of the case date back to 2002, when a Kansas City psychiatrist claimed to have been treating Elvis, now using the name of his stillborn twin brother, Jesse Garon Presley. The allegation was picked up by a local Fox station, Fox 8 News, which attempted to match a DNA sample provided by the man claiming to be Jesse to that of Elvis.

Times Archive, 1977: Elvis Presley dies in hospital

Elvis Presley, the millionaire singer idolized by teenagers in the late 1950s, died this evening in Memphis, Tennessee. He was 42

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A Memphis businessman and collector stepped forward with some of Elvis' medical records, including tissue samples from two liver biopsies and his post-mortem. The samples were sent for testing and came back negative - but not just between Jesse and Elvis.

It was also discovered that the DNA from the singer's liver did not match that from his post-mortem, a claim that has supported many of the subsequent web-based theories.

Astonishing though this finding appeared to be, it also heralded a dead end for the Fox investigation, or so the station thought. Earlier this year it was contacted by Ms Presley, then Alice Elizabeth Tiffin, who had her own interest in Elvis.

Ms Presley had recently discovered that she was adopted, and was casting around for answers. Prompted by friends who saw a likeness between her sons and the Pelvis, she began to wonder if she could possibly be a genuine lovechild.

This was not such a leap as might be imagined: her mother had lived close to Graceland in her youth and was friendly with Elvis and his family, a fact documented in newspapers of the day.

With the station's help, she began an investigation which soon took some curious turns.

First, Ms Presley collected DNA samples from two of Elvis's first cousins, one maternal, one paternal. These were sent to an Arizona lab to be tested against her own DNA, and the sample from the man claiming to be Jesse.

Incredibly, Jesse was found to be biologically related to both Elvis cousins , proving, at least in Ms Presley's mind, that he was indeed the King.

Then her DNA was tested against Jesse's, and again a match was found. However the relationship was not father-child, but siblings.

Finally, Ms Presley's DNA was tested against both cousins. It came back a match for the paternal side, but not the maternal. This final piece of evidence confirmed what Ms Presley now suspected. It was not Elvis Presley who had impregnated her mother: it was his father, Vernon.

She was Elvis's half sister.

Ms Presley stresses that when she first contacted the station, her only interest was in the Elvis DNA. She had never believed Jesse's claims, assuming that he was just another member of the lunatic legions clamouring for a piece of the Graceland pie. Nor had she given credence to classic Elvis conspiracy theories, with their allusions to the waxlike appearance of the King's corpse and the misspelled name on his tombstone.

Now she is a believer. “He has to be [Elvis]. There's no two ways about it. You can't fake the DNA.”

But can you?

While the respected forensic scientist who tested the DNA, Tony Tambasco, said that the results “look like wow”, he acknowledges that many unrelated people can exhibit similar DNA markers. The only way to prove it irrefutably would be to test Lisa Marie, he said, adding: “The issue could easily be resolved.”

Elvis Presley Enterprises said it would not provide a sample because there are so many similar claims that if it did so in this case, it would be obliged to do it for all. Nevertheless it is being forced to defend itself in the courts. Attorney William Bradley said: “Obviously, we would prefer that (the judge) not reopen it but these are matters we will address in court.”

And the claims that Elvis is alive? “Just nonsense,” the estate said.

Nonsense or not, the case has transfixed Tennessee residents. Chris Thomas, a clerk at the probate court which is handling the suit, said locals are startled at the apparent evidence. “A lot of people have been surprised and curious as to what's there.”

However, he added: “All the money's been distributed - there's nothing for this lady to get monetarily.”

For her part, Ms Presley insists she is motivated only by the desire to get to know her brother. “I think it would be such a travesty that he really does die and I never get to meet him,” she says.

Whether fact or fiction (and it must be noted that Ms Presley's biological mother insists it is the latter) the story has proved fertile ground for fans convinced their idol will one day rise again. In an internet poll conducted by Fox News 8, a clear majority, 56 per cent said they either "absolutely" believed Elvis faked his death, or that he might have done. In their minds at least, the King still lives on.

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