The anguished life of Marvin Gaye ended on April 1, 1984, at the home in Los Angeles he had bought for his parents, when a bullet from a .38 calibre revolver fired by his father tore into his heart. With the kind of savage irony that seemed to permeate every area of Gaye's life, the death weapon had been a gift some weeks previously from the singer to his father.

"I think that giving the gun to his father was quite intentional," considers David Ritz, the author of Divided Soul, a startlingly rich and infinitely detailed biography of the singer. "Marvin knew what he was doing: he wanted to die. Only four days before he was shot he'd jumped out of a car that was travelling at 60mph along a Los Angeles freeway."

Originally hired as Gaye's official biographer, Ritz eventually fell out with his subject, but not before he had talked with Gaye extensively and been given access to his family. As a result, after the killing Ritz possessed a goldmine of material for what is unquestionably a definitive pop music biography.

In the news reports of Gaye's death, the singer's father was painted as a God-fearing preacher, exacting Old Testament retribution on an unrepentant, hardened sinner. Little about Marvin Pentz Gay Sr, could have been further from the truth – except, that is, for the Old Testament aspect. For the church in which he was a minister, the House of God, was an eccentric Southern sect that drew equally from orthodox Judaism and Pentecostal Christianity: the Sabbath is held to be Saturday; from Passover to Harvest Festival women wear only white, their pillbox hats adorned with pale blue Stars of David; on the Day of Atonement, disciples of the House of God fast and pray in church for the entire 24 hours.

As with so many soul singers, it was in church that Marvin Gaye gave his first vocal performances. But even here lay the roots of one of the myriad contradictions that collided ceaselessly within him: for his father's church saw the use of music for secular purposes as an unredeemable sin. Here, in the certainty that he was not fulfilling his spiritual potential, lay the cause of much of the self-disgust that shadowed Gaye for most of his career. As Ritz says: "Marvin was constantly enraged at himself for not developing as an artist in a religious way. He was angered by his lack of self-discipline, by the fact that-he could never give up cocaine, which he started doing in the early years of Motown."

A history of violence ran like a curse through the Gay (Marvin added the 'e' to his name) family on his father's side. Ritz again: "Marvin's mother told me that there was all kinds of violence in the family in Kentucky. She said that one of her brothers-in-law had actually killed a woman. Marvin was haunted by this background: he felt he must have inherited his father's sin. But it was just as bad on the mother's side: her father actually once shot her mother, though he didn't kill her, and he died in a hospital for the insane."

And, if this wasn't enough, a thick vein of sexual confusion ran through Gaye's family life. Ritz: 'His father was the only one of several brothers who was not openly gay. But all the same he loved dressing up in women's clothes and would frequently wear dresses, suspender belts and stockings around the house. I think he must have passed this on to his son, because Marvin told me that he himself had a fascination with dressing up in women's clothes, and would from time to time indulge himself."

The merciless, sadistic beatings that his frequently drunken father would deal him as a child led to Gaye growing ever closer to his mother, a relationship that only intensified the turmoil within him. And the family surname helped not one jot: "The name Gay was far too close to home. He was intensely frightened that he'd also inherited that tendency of his father's family, but it was something he was determined to ignore or repress. I remember once after one of his concerts a man shook his hand in what could only be described as a gay way. As we drove off Marvin was protesting to me that he should have beaten the shit out of the guy. There was an awful lot of over-compensation – it wasn't anything he wanted to confront at all."

Marvin Gaye's personal battle, says Ritz, took place on that thin line that separates spirituality and sensuality, the difference between the truth of his masterpiece, 'What's Going On', and the Me Generation paean to sex of 'Let's Get It On'. "He became trapped in the image of Marvin Gaye as a sex symbol. Marvin was really a very shy, retiring man. But as the pressures on him became greater and greater, his humanity became diminished. One of the reasons he did so much cocaine was to impose upon himself the need to get out onstage and shake his cock about. In his own mind he was only a sex symbol – though that certainly wasn't merely what his audiences saw him as. But he wound up attempting to become that self-image, and so had contempt for himself.

"In the latter part of his career," continues Ritz, "he was plagued by impotence, which was the result of both the cocaine and the desire to live up to his own myth, having to live up to all those women he was supposed to satisfy: if you had 1,000 naked women lying there in front of you, your dick might crawl away and hide. Also, Marvin by nature was not a promiscuous man, and he just couldn't pull off the act. But he could never really see women as human beings – they were either angels or harlots: his mythologising of women caused him immense pain."

Never comfortable with the superstud ethos of black ghetto life in Washington where he grew up, Gaye didn't lose his virginity until he was 17 when he enlisted for a short time as a regular in the USAAF. And this first sexual encounter was with a prostitute in the local cathouse, a cathartic experience, as he told Ritz: "I felt betrayed. Sex was crude and frightening. Suddenly I could see a world of pure sex where people turned off their minds and fed their lusts, no questions asked. The concept sickened me, but I also found it exciting."

On the road in later life, as desirable women clamoured for a piece of him, Gaye would frequently ignore their offers and return alone to his hotel room, to wake in the arms of whichever hooker he had hired for the night. "Prostitutes protect me from passion," he said in an interview with Actuel magazine the year before he died. "Passions are dangerous. They cause you to lust after other men's wives."

Ritz does not however confine his story to the sordid and salacious details of Marvin Gaye's life. Rather, he examines them in the context of Gaye's art, a large body of work he sums up in the penultimate paragraph of Divided Soul: "He had the rare courage to pour the pain of his troubled life into his art, and, as a result, his art was expanded and enriched. His creations, like prayers, were filled with a longing for love, not selflove, but a far wiser, far larger love, a love that transcends ego and turns our hearts back to the source of art itself. Marvin's music – the sexual as well as the spiritual – is God-given, God-inspired, God-blessed."
Like Gaye's music, Divided Soul is from the heart. The singer's story is interwoven through an erudite, fascinating account of the entire soundscape of soul music, especially the frequently shadowy goings on at Motown Records, Marvin Gaye's recording home for 20 years. Though Gaye delivers some choice quotes in the direction of Berry Gordy, the label's despotic founder ('Diana Ross made millions for Berry, and a few dollars for herself'), the emerging picture of Gordy is far more complimentary than legend would have you believe: inflated record advances for Gaye; a genuine concern for the wellbeing of his unpredictable star, and an almost paternal guiding role – which, naturally, only served to further confuse a man always bewildered by the notion of father figures.

In fact, in his early years with Motown, Gaye was always prepared to compromise if it would provide him with a hit, and wasn't above promoting his career by the most pragmatic of procedures. It was not only deep love but also unbridled ambition that at the age of 20 impelled him to marry Anna Gordy, Berry's sister, a woman 17 years older than himself. "Certainly Marvin loved Anna," Ritz says. "'But there was also a part of him that was extremely Machiavellian: he knew he needed an advantage to get ahead in Motown, and he seized his opportunity."

The marriage was as divided and torn as Marvin Gaye himself: one moment sweet and loving, the next fractious and bitter, as this awkward couple indulged their infinite capacities for inflicting pain on each other.

Faithfulness was never the cornerstone of the relationship but a marriage of sorts lasted for years until, while recording 'Let's Get It On' in 1973, Gaye met Janis Hunter at a Los Angeles studio. The record's atmosphere of unrestrained sensuality was inspired by the sight of the woman who would become his next wife. As though destiny had deemed that the life of Marvin Gaye should be awkwardly intertwined with twists of irony. Hunter was 17 years younger than the singer.

The break-up of Gaye's marriage with Anna was as messy as their years together had been. Increasingly dependent on cocaine, with its attendant side-effect of a purgatory of paranoia, Gaye became convinced that Berry Gordy was conspiring with his sister against him. Not true, claims Ritz: desperate to keep the records coming from his huge-selling solo artist, Gordy consciously stepped away from the conflict.

Marvin's final, most public comment on the marriage came like some attempt at a Grand Cosmic Joke. Despite lavish earnings, he was always broke (he estimated he had spent at least a million dollars on cocaine) and, as his divorce settlement, he agreed to give the entire proceedings of his next album to Anna. Except that Anna had not expected the LP, Here, My Dear, to provide in its songs a precise account of the tortured years she and Marvin had spent together.

Yet the last laugh may have been Anna's: in 1979 Jan Gaye left Marvin for Teddy Pendergrass, who was challenging Marvin for his title of high priest of bedroom soul. The effect on Marvin was shattering, the final blow on top of escalating financial problems that had ended in bankruptcy. His immediate solution was to flee to Hawaii. There he first plotted to kill Jan, but then attempted to kill himself instead, by snorting an ounce of cocaine in an hour.

Gaye moved to London, and his addiction to the drug deepened: he was free-basing regularly and his moods knew no rhythm as they swung in seconds between elation and the most profound, blackest depression. His salvation, temporary as it was, took a curious form. A Belgian businessman spirited Marvin Gaye away from London to his pension in Ostend. There's a touching whimsicality about the idea of Marvin Gaye, recording guru of New Age sexuality and spirituality, fighting back against the personal forces of darkness that had all but overthrown him by jogging along the windswept Ostend seafront.

Released from Motown, Marvin Gaye signed with CBS and released the Midnight Love album. A slighter work than it was made to seem by the hyperbole that surrounded its release, it nonetheless gathered large worldwide sales, as did the 'Sexual Healing' single.

But fresh torment accompanied these successes: obliged again to tour America, Gaye performed many of the shows in a manner hardly removed from the spectacle offered by Elvis Presley in his last days, every trace of dignity eradicated until all that remained was the unendurably saddening spectacle of self-parody: during the finale of 'Sexual Healing', in an ever more desperate effort to satisfy what, in his delusions, Marvin Gaye believed were the demands of his female fans, he stripped off his clothes down to his underpants, revealing a paunchy, rapidly deteriorating figure.

Gaye's temporary respite from the devil of cocaine had dissolved as soon as he returned to America: now, backstage and in his hotel room, he was not only snorting and free-basing but actually eating the insidiously evil white powder. After the Midnight Love tour he returned to Los Angeles, moving into the home on Santo Monica Boulevard he had bought for his parents. There his father was indulging himself with alcohol as much as Gaye was with cocaine. Marvin's bedroom was separated from his father's by his mother's – a symbolic representation of her role throughout his life.

Mentally unhinged, crippled with a paranoia that only amplified the portents and signs of his own end that he saw everywhere, Marvin remained in his room for days on end. On one of the few occasions that he ventured out he was found wandering along a nearby freeway underpass, wearing three overcoats and his shoes on the wrong feet.

On the morning of April 1, 1984, the day before Marvin's 45th birthday, his father was storming around the house, searching for a missing letter. Certain that his wife knew of its whereabouts, he barged into his son's bedroom where she and Marvin were sitting, talking. The father screamed at his wife in fury. Marvin leapt to her aid, pushing his father out of the room and punching him.
According to his mother, Gaye's father had publicly proclaimed that if his son were ever to hit him, he would kill him. And he did, returning with the gun several seconds later.

Marvin Pentz Gay, Sr, pleaded no contest to a charge of voluntary manslaughter. He was sentenced to five years probation. Marvin Gaye's ashes were thrown to the wind from a ship at sea by Anna and his three children.