The widow of the pilot of United Flight 93 on Sept. 11, 2001, died of heart failure caused by accidental alcohol and drug overdose, according to an autopsy released Friday.

Sandy Dahl, the wife of Captain Jason Dahl, died in May, at the age of 52 near Denver. The autopsy report from the Jefferson County Coroner's office in Colorado said alcohol, painkillers, anti-depression drugs and anti-anxiety drugs were found in her system, The Denver Post reported. The coroner's office found that Dahl's death was "consistent with the combined impact of alcohol and multiple drug toxicity," according to the Post.

The report also listed an abnormal heart condition as a possible contributor to her death, Denver's NBC-affiliate KUSA reported.

Related: VP Biden draws on personal grief in comforting Flight 93 families

Dahl, a former United flight attendant, founded the Captain Jason Dahl Scholarship Fund to provide scholarships for students wanting to attend commercial flight training school. Dahl also became a public face for 9/11 families.

On Sept. 11, 2001, United Flight 93 crashed into a Pennsylvania field after being taken over by terrorists. Evidence suggests that crewmembers and passengers on Flight 93 fought back, which was believed to be headed for the U.S. Capitol.

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