Concert promoters at AEG Live were wrong not to investigate Conrad Murray before hiring the doctor to care for Michael Jackson, a Los Angeles jury has heard in the opening statements of a multi-billion dollar wrongful death trial. The King of Pop's mother, Katherine Jackson, is currently suing AEG Live bosses, the promoters behind the superstar's doomed This Is It comeback concerts, claiming they were negligent in ignoring her son's life-threatening health concerns and hiring Murray, the medic who was convicted of involuntary manslaughter for administering the fatal dose of propofol, which claimed the hitmaker's life in 2009. Opening statements in the case began on Monday (29Apr13) and during the proceedings, Brian Parish, a lawyer for the Jackson matriarch, accused AEG chiefs of failing to look after the star's best interests by pushing him to the limit during rehearsals - even though the 50 year old had a history of turning to drugs to cope with stress. Speaking to a jury of 12 men and women, Parish said, "Michael paid the ultimate price (for their negligence). He died... His stirring voice, his musical genius, his creativity and his generosity and his huge heart was extinguished forever." Meanwhile, AEG executives have denied any wrongdoing, insisting they weren't aware of the tragic singer's addiction to prescription drugs or responsible for hiring Murray as the star's tour doctor. The trial is ongoing and expected to last several weeks. Katherine, her son Randy and daughter Rebbie were all present for the hearing, according to the Associated Press. More than 200 people - among them stars like Quincy Jones and Prince - have been named among the witnesses for both the defence and the prosecution.