>> conrad robert murray, guilty. >> reporter: jackson's doctor conrad murray is already behind bars for involuntary manslaughter. but now jackson's mother and three children are suing the concert promoter that paid murray's salary. the cornerstone of their case, an e-mail from aeg's ceo 11 days before jackson's death. we want to remind murray that it is aeg, not mj who is paying his salary. we want to remind him what's expected of him. >> the worst thing that aeg's got going for them, the worst, is that e-mail. >> reporter: so once they agreed to pay $150,000 a month you're saying they're liable. >> right. and i'm going to say that's going to go a long way. >> reporter: but aeg's lawyer told them the promoters didn't hire murray. jackson did. and the treatment plan was subject to doctor-patient privilege. the truth is michael jackson fooled everyone, aeg's lawyer said, he made sure no one, nobody knew his deepest, darkest secrets. the plaintiffs call their first witness. for "good morning america," david wright, abc news, los angeles. >> and the trial expected to last many, many months.