DENVER (CBS4)– Testimony began on Tuesday in the murder trial of a Highlands Ranch man accused of pushing his second wife to her death off a cliff in Rocky Mountain National Park on their wedding anniversary.

Henthorn is accused of the murder of his ophthalmologist wife, Dr. Toni Henthorn, who fell to her death in September 2012 during an anniversary hike with her husband.

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Harold and Toni Henthorn (courtesy to CBS)

Harold and Toni Henthorn (courtesy to CBS)

There were no other witnesses. Harold Henthorn has pleaded not guilty.

Prosecutors believe Henthorn pushed his wife off a cliff to her death. They also believe Henthorn killed his first wife, Lynn, who died in a freak accident in 1995. However, that case was ruled an accident by Douglas County authorities, although they now say they are taking a second look at the case in light of the charges against Henthorn in his second wife’s death.

Harold and Sandra Lynn (courtesy to CBS)

Harold and Sandra Lynn (courtesy to CBS)

Henthorn was never charged in connection with his first wife’s death.

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Prosecutors have submitted a lengthy witness list and have indicated they may have more than 300 exhibits.

Henthorn’s attorney, Craig Truman, has listed only a few potential witnesses and only a few exhibits.

Toni’s brother testified that Henthorn had her cremated just days after her death, something he said was against the wishes of her family.

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The trial is expected to continue for three weeks.