Los Angeles (CNN) -- Elvis Presley's death became a controversy at the Michael Jackson wrongful death trial as a man who promoted both artists' last tours testified. AEG Live Co-CEO Paul Gongaware testified Wednesday that Presley died of a drug overdose, but when his own lawyer questioned him Thursday he changed his testimony to say Elvis died of a heart ailment. Presley collapsed in the bathroom of his Memphis, Tennessee, mansion -- Graceland -- on August 16, 1977, at the age of 42. While his death was ruled the result of an irregular heartbeat, the autopsy report was sealed amid accusations that abuse of prescription drugs caused the problem.
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AEG Live Co-CEO promoted last tours of Elvis and Michael Jackson
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Jackson lawyers say his experience with Elvis should've prepared him for MJ
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AEG's lawyer works to rehab witness after repeated "I don't recall" answers
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Paul Gongaware wrote 'smoking gun' e-mail
Promoter: 'I kind of knew what was going to happen' to @placeholder