Now, a new book suggests the singer may have met his maker with a psychedelic bang after all.

Sam Bernett, a former Paris nightclub manager, has claimed that The Doors' frontman died on 3 July 1971 in a lavatory cubicle at his club. The suspected cause of death: heroin overdose.

Although rumours of this have circulated since Morrison's death 36 years ago, no witnesses have come forward . . . until now.

The author, who managed the venue in question, believes two drug dealers carried Morrison out of the club and took him to his apartment. After arriving there, Bernett claims, Morrison was thrown into a bath in an attempt to revive him.

Bernett writes in the French-language book The End: Jim Morrison: "The flamboyant singer of The Doors, the beautiful California boy, had become an inert lump crumpled in the toilet of a nightclub."

Commenting on the claim, Phil Alexander, the editor-in-chief of Mojo, said: 'When you talk to anyone that knew Jim, such as Alice Cooper, it was never a question of was he going to die, it was a question of when. Though whether it happened in a club or in a bath is neither here nor there. He was an excessive guy and that's what defined him over the years."

Bernett, who was in his early 20s on the night that Morrison died, claims he kept his story quiet until his wife suggested he pen the book last year.

His story is corroborated by the photographer Patrick Chauvel, who recalls helping the drug dealers carry a prostrate Morrison out of the club. "I think he was already dead, " he said. He added that he thought an ambulance would have been called if Morrison had been breathing. "I don't know, " he concluded. "It was a long time ago, and we weren't drinking only water."

Morrison, who was 27, moved to Paris in March 1971 after he was convicted of indecent exposure at a 1969 concert and promoters started to cancel his shows. He arrived in Paris accompanied by his girlfriend, Pamela Courson, to wander the streets . . .

an increasingly shambolic figure carrying a plastic bag full of writings. He piled on the pounds, punctuating his life with parties at Bernett's club.

Bernett claims that on the night of his death, Morrison went to the club and was joined by two men who sold him heroin. At one point he noticed Morrison had gone. Later, a bouncer broke down the door of a locked lavatory cubicle and the singer was discovered.

Bernett, who went on to become a radio personality and a vice-president of Disneyland Paris, said he asked a doctor who was in the club to examine Morrison.

He writes: "When we found him dead, he had a little foam on his nose, and some blood too, and the doctor said, 'that must be an overdose of heroin'."

The former nightclub manager added that he did not see Morrison take any heroin that night, but said he was known to snort the drug because he was afraid of needles.

He claims the two drug dealers insisted Morrison was only unconscious and carried him from the club.

Bernett says he urged those present to call paramedics, but was ordered to stand aside by his boss, who did not want a scandal.

The account contradicts that given to police by Pamela Courson, who said the couple went to the movies before falling asleep. She claimed Morrison awoke in the night feeling ill and took a hot bath, and that she later found him dead in the tub.

Morrison was buried on 7 July 1971. There was no post-mortem examination.