LOS ANGELES: Michael Jackson, defined in equal parts as the world’s greatest entertainer and perhaps its most enigmatic figure, was about to attempt one of the greatest comebacks of all time. Then his life was cut shockingly — and so far, mysteriously — short. The 50-year-old musical superstar died today just as he was preparing for what would be a series of 50 concerts, starting July 13 at London’s famed 02 arena. Jackson had been spending hours and hours toiling with a team of dancers for a performance he and his fans hoped would restore his tarnished legacy to its proper place in pop. An autopsy was planned for today, though results were not likely to be final until toxicology tests could be completed, a process that could take several days and maybe weeks. However, if a cause can be determined by the autopsy, the results will be announced, said Los Angeles County Coroner Investigator Jerry McKibben. Police said they were investigating, standard procedure in high-profile cases. Jackson died at UCLA Medical Centre after being stricken at his rented home in the posh Los Angeles neighbourhood of Holmby Hills. Paramedics tried to resuscitate him at his home for nearly three-quarters of an hour, then rushed him to the hospital, where doctors continued to work on him. “It is believed he suffered cardiac arrest in his home. However, the cause of his death is unknown until results of the autopsy are known,” said his brother Jermaine. Cardiac arrest is an abnormal heart rhythm that stops the heart from pumping blood to the body. It can occur after a heart attack or be caused by other heart problems. Jackson’s death brought a tragic end to a long, bizarre, sometimes farcical decline from his peak in the 1980s, when he was popular music’s premier all-around performer, a unifier of black and white music who shattered the race barrier on MTV, dominated the charts and dazzled even more on stage. His 1982 album, Thriller, which included the blockbuster hits Beat It, Billie Jean and Thriller, is the best-selling album of all time, with an estimated 50 million copies sold worldwide. Yet after selling more than 61 million albums in the US and having a decade-long attraction open at Disney theme parks, Jackson died reportedly awash in about $400 million in debt, on the cusp of a final comeback after well over a decade of scandal. He was perhaps the most exciting performer of his generation, known for his backward-gliding moonwalk, his feverish, crotch-grabbing dance moves and his high-pitched singing, punctuated with squeals and titters.