TMZ Investigates: Lisa Marie Presley: Unending Tragedy reveals information about the cause of death of Elvis's only child. A TMZ investigation dives deep into the current unsettled conflicts revolving around Lisa Marie Presley's unforeseen passing, including never-before-heard details about the money Lisa left behind and who will inherit the fortune. As for who will gain custody of Lisa's 14-year-old twins, TMZ Investigates has the details. In regard to which family members continue a relationship with the twins, TMZ knows a conflict is brewing. The special also will bring to light the truths behind tragedies Lisa endured during her life, such as the demise of her marriage to the "King of Pop," Michael Jackson, in which TMZ exclusively speaks to close friends and family who state their marriage was real, and truly heartbreaking for both parties when they decided to divorce.