A Colorado man was convicted on Monday of murdering his wife. Prosecutors said that he pushed his wife off a cliff at a national park so he could collect millions of dollars in life insurance money. The woman fell to her death at a national park three years ago.

Fifty-nine-year-old Harold Henthorn was found guilty of first-degree murder. His wife, Toni, died in September 2012, after she fell 120 feet at Rocky Mountain National Park.

May Have Killed His First Wife, Too

During the proceedings, prosecutors further accused Henthorn of murdering his first wife, who died 20 years ago. However, Henthorn has yet to be charged for that case. His first wife was killed while changing a tire on the couple's car. She was under the car when, according to Henthorn, it came off its jack and fatally crushed her. Henthorn collected $496,000 in life insurance money for his first wife's death.

Henthorn Was Set to Receive $4.5 Million in Insurance Money

Prosecutors argued that, because of his wife's death, Harold Henthorn was set to receive $4.5 million in life insurance money and had access to approximately $1.5 million worth of investment and bank accounts.

Convicted on Mostly Circumstantial Evidence

Evidence in the murder case was mostly circumstantial. Prosecutors, however, accused Henthorn of giving wildly varying accounts of how his wife came to fall from the cliff. In addition, a National Park Service agent said that they found a park map in the couple's car, which featured an "X" drawn on the place where the woman took her fall. According to investigators, Henthorn was unable to explain his reason for putting an "X" on the map.

Henthorn did not testify in his defense and no defense witnesses were called forward. His sentencing hearing has been scheduled for Dec. 8, and he is expected to receive a mandatory sentence of life in prison.