LOS ANGELES (CBSLA.com) — Michael Jackson’s mother broke down in tears Thursday as the wrongful death trial pitting her against entertainment giant AEG Live continued.

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It was an emotional day in court as Katherine Jackson listened while e-mails between AEG executives describing how her son looked in the days before his death were reviewed.

Some of the e-mails described Michael Jackson appearing “weak and fatigued” as he prepared for his This Is It comeback concerts in London, produced by AEG.

One e-mail from concert director Kenny Ortega described how the singer would have been distressed at the thought of halting plans for the show.

“It would break his heart if he pulled the plug,” the e-mail read.

As KCAL9’s Randy Paige reports, the details appeared to be too much for Katherine Jackson, who left the courtroom and did not return after the lunch break.

Katherine Jackson is suing AEG Live for what she alleges was negligence on the part of the firm in the hiring of Michael Jackson’s former personal physician, Conrad Murray, to look after him during the concert series.

A jury found Murray guilty of involuntary manslaughter in November 2011 for administering the dose of anesthetic propofol that killed Michael Jackson in June 2009 at the age of 50. Murray is currently serving a four-year sentence in a Los Angeles County jail but is appealing the conviction.

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Jackson family attorney Brian Panish is trying to prove Murray was hired by AEG, not Michael Jackson, for This Is It.

Panish pointed to an e-mail dated June 14, 2009 sent from the CEO of AEG to the show’s director.

“We want to remind him, (Conrad Murray) that it is AEG, not MJ (Michael Jackson), who’s paying his salary. We want to remind him what is expected of him,” the e-mail reads.

Panish questioned AEG Live General Counsel Shawn Trell about the memo in court Thursday.

“Is it a conflict of interest to tell a doctor treating a patient he needs to know what’s expected of the person who is paying for him rather than the patient?” Panish asked.

Trell said he did not believe there was a conflict of interest because all parties involved shared the same interest: Michael Jackson’s good health.

Trell went on to say the tour could have always been rescheduled.

AEG Live co-CEO Paul Gongaware is expected to take the stand on Friday.

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The trial continues.