More skeletons are now popping out of the King of Pop's Neverland closet at the hearing for wrongful death case that Michael Jackson's mother, Katherine Jackson, filed in a San Francisco court against the producers of his London concerts.

Marvin Putnam, the lawyer of AEG, the concert producer, pointed out that Michael was so good at hiding his anesthetic drug addiction that the company was unaware of his bad habit as apparently did also his family.

"The truth is, Michael Jackson fooled everyone ... He made sure that no one, nobody, knew his deepest darkest secrets," AP quoted Mr Putnam.

He said that while no doubt, the death of Jackson at age 50 in 2009 is a terrible tragedy - for which the Jackson matriarch and the singer's three minor children are asking for $40 billion damage for lost earnings - the tragedy was not AEG's making, but Michael's.

Brian Panish, the lawyer of Mrs Jackson, insisted that AEG created a conflict of interest for cardiologist Conrad Murray which forced him to choose the large salary and compromise the singer's healthcare. He claimed that the concert producers ignore warning signs about Michael's deteriorating health, but at the same time admitted to jurors that Jackson's last 25 years was spent struggling with prescription drug abuse.

But Mr Putnam stressed it was his use of propofol that caused the death of Jackson. "One thing became very, very clear ... While the world may not have heard of propofol, Mr Jackson certainly had. The evidence is going to show you that he had been using that drug for years and years," the AEG lawyer said.

Mr Putnam pointed to physician-patient confidentiality as the reason why the public did not know of the singer's addiction to propofol use, but he added that Debbie Rowe, the former wife of Jackson and a nurse, would tell the court that Michael had been using the anesthetic since the 1990s.

"Mr Jackson got very, very good at his addiction ... He didn't let anyone see it. Not his staff, not his children. This was the private Michael Jackson," Mr Putnam added.

The AEG lawyer warned that more ugly stuff will come out in the continuing drama of the Jackson Death Trial expected to last for three months.