Williamson County authorities are investigating after Sherrilyn Kenyon, a best-selling fantasy author, accused her estranged husband of poisoning her.

Kenyon, known for her “Dark Hunter” series, said a recent medical test revealed she had high levels of lithium, tin, barium, platinum and thorium in her body, The Tennessean reported Tuesday. The chemicals caused hampered breathing, hair loss, broken teeth and nausea, she said.

“[The doctor] said there’s no way this could have happened naturally or environmentally,” Kenyon told the newspaper.

The 53-year-old author accused her estranged husband, Lawrence Kenyon, and his assistant, Kerrie Ann Plump, of giving her tainted food over the last three years, the newspaper reported. Kenyon believes her husband is trying to kill her in order for him to inherit her estate. The two are in the middle of a divorce.

“I thought I had a happy marriage. Compared to what I was used to, he was awesome,” Kenyon told The Tennessean. “No marriage is without problems, but it wasn’t like my mother and father, where they threw furniture at each other.”

Kenyon filed a civil lawsuit against her husband and assistant in Williamson County alleging assault by poisoning and other wrongful acts. She is asking for up to $20 million in damages, The Tennessean reported. The Willamson County Sheriff’s Office also assigned a detective to look into her allegations.

Sean Aiello, Lawrence Kenyon’s lawyer, dismissed the allegations, according to the Los Angeles Times.

Sherrilyn Kenyon is known for her urban fantasy and paranormal romance novels. Her books Devil May Cry and No Mercy were both featured on The New York Times’ Best Sellers list.