Lisa Marie Presley is offering an explanation for why she’s in debt — she says an ex-manager sunk $100 million into a failed investment, and now she’s suing him. According to this:

Lisa Marie says Barry Siegel ran the Trust Elvis Presley left for his daughter — and in 2005 he sold off 85% of her interest in Elvis Presley Enterprises for $100 mil. In the lawsuit docs, obtained by TMZ, she says Siegel took all of that cash and invested in a company called Core Entertainment.

Core is the parent company of “American Idol.” You could kinda understand his move — 2005 was the heyday for ‘Idol.’

Unfortunately, Core went belly-up in 2016 and, according to the docs, Lisa Marie’s stock plummeted and she lost $24.5 million. In the suit, she also blames Siegel for not warning her she was spending beyond her means. For example, she says the Trust already had 2 mortgages that were under water … when she bought a $9 million English estate. She says Siegel never sounded a single alarm.

She says the Trust was left with a mere $14k in cash after Core went bankrupt.

TMZ broke the story … Lisa Marie says she’s $16 mil in debt …