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Tomorrow makes the 4th anniversary of the death of Michael Jackson.  In a Los Angeles courtroom, the trial continues in the wrongful death lawsuit the Jackson family has filed against concert promoters AEG.   The family feels that since the promoter hired Dr. Conrad Murray, who was found guilty of involuntary manslaughter in the singer's death, they are responsible as well.

Last week, a doctor told the courtroom that Michael Jackson went without "real" sleep for 60 days leading up to his death.   Jackson had been receiving nightly infusions of propofol, a surgical anesthetic for about two months to treat his insomnia as he rehearsed for a series of comeback concerts. 

The testimony raises questions about how long a person can survive with shut-eye, and whether it matters what type of sleep a person slips into when they snooze.   A Harvard sleep scientist who testified at the trial said that even if the drug made Jackson feel well rested, it would have sent him into a superficial slumber each night.  

Another scientist testified that lack of proper sleep has been linked to many diseases and conditions, but added that there is no evidence that sleep deprivation itself will kill anyone.  He said it can lead to conditions that could eventually cause death.