Victoria Siegel, the star of the 2012 documentary film "The Queen of Versailles," was found dead in her family's home in Windermere, Fla. last month. A recently released autopsy concluded that her death was caused by an accidental overdose, the Associated Press reported.

Victoria's death was due to toxic amounts of methadone and sertraline, according to the report by the Orange County Medical Examiner's Office. The autopsy found a significant concentration of both drugs.

Siegel was unresponsive when she was found by a housekeeper in her family's mansion on June 6 and she was pronounced dead at a hospital, according to the AP.

The 18-year-old reportedly struggled with addiction to methadone, a drug that is commonly prescribed to control seizures, according to the Center for Disease Control and Prevention's website. Sertraline, sold as Zoloft, is used to treat depression. Siegel had previously gone to rehab for her addiction to methadone, family attorney Michael Marder said.

"Unfortunately she became dependent and struggled with this condition," Marder told People. "She voluntarily underwent rehabilitation and was working hard to address this problem."

Siegel was the daughter of Westgate Resorts founder David Siegel and his wife Jackie, a former Mrs. Florida America. The family was featured in the 2012 documentary film "The Queen of Versailles" which followed their lavish lifestyles.