Michael Jackson's mother and his children have begun court action in Los Angeles to sue the singer's concert promoters for millions of dollars in damages.
Katherine Jackson and his three children say AEG Live should be held liable for the 50-year-old's death in California 2009.
Their lawyer says the promoters failed properly to vet the doctor convicted of causing the singer's death from a drug overdose.
The promoters say they did no wrong and could not have foreseen Jackson's death on the eve of his comeback tour.
Millions of dollars are at stake in the trial, which could last up to 90 days, the BBC reports.
Brian Panish, who represents Jackson's relatives, told a court in Los Angeles on Monday that AEG Live was the only party that maintained it was unaware of Jackson's addiction to prescription drugs.
"Over the years Michael's family and people who knew him believed he had a problem with prescription medication," Mr Panish told a jury of six men and six women.
"His stirring voice, his musical genius, his creativity and his generosity and his huge heart was extinguished forever," he said, adding that jurors would have to decide who was responsible for the star's death.
But AEG Live's lawyer Marvin Putnam said Jackson's closely guarded private life left the promoters in the dark about his drug dependence.
"The truth is, Michael Jackson fooled everyone. He made sure that no-one, nobody, knew his deepest darkest secrets."
The case is expected to focus on the last months of Michael Jackson's life, his financial history and overall health, and may feature testimony from his children.
It is also expected to focus on the actions of Conrad Murray, the former cardiologist convicted of involuntary manslaughter in 2011 for administering a combination of sedatives and the anaesthetic propofol that killed Jackson.
The Jackson family claims in its suit, filed in 2010, that AEG Live had not properly investigated Murray's background before he was hired to serve as Jackson's personal physician.
Murray was to be paid $US150,000 a month during the This Is It concert series, but Jackson died before the tour began. Murray is in prison, appealing against his conviction.