A Colorado jury of eight women and four men deliberated for 12 hours over two days before deciding Monday afternoon that Harold Henthorn, 59, was guilty of murdering his wife three years ago.

Jurors concluded that Henthorn pushed his second wife, Toni, over a ledge during a 12th anniversary hike in Rocky Mountain National Park on September 29, 2012. Toni, 50, a successful Denver ophthalmologist died at the scene after tumbling 128-feet down a steep cliff.

Although Henthorn claimed Toni accidentally fell as she was taking pictures, investigators searched Henthorn s Jeep and found a map with a pink “X” marking the spot where Toni went over the edge. Henthorn told different stories about her fall, and tried to get a friend to say that the map was drawn for the friend. Henthorn’s case garnered national attention, with PEOPLE featuring the case on its Dec. 14, 2014 cover.

Other evidence revealed that Henthorn had lied about his fundraising business, and hadn t reported any income for years. Additionally, he had took out three life insurance policies totaling more than $4.5 million on Toni.

Dr. Barry Bertolet, Toni s brother, was the first witness for the prosecution, and sat with his family in the courtroom during the eight days of testimony. Bertolet tells PEOPLE that his “aha moment” was cell phone information detailing “how Harold had been in the park nine times in the eight weeks before their trip.”

For Tami Abbruscato, Toni’s co-worker who also testified during the trial, the “smoking gun” came at the end of the prosecution s case: “The last piece of evidence showed that a personal bank account Toni opened in June of 2012 was depleted on Sept. 27th, two days before her death,” Abbruscato tells PEOPLE. “It was only $6800, but it was for cash. I ve seen her signature a zillion times and that clearly was not her signature on that check. That man wanted every single dime he could capture.”

Abbruscato believes Toni may have been taking steps toward leaving Henthorn. The Bertolet family agrees.

Barry Bertolet says: “I think the fact that they were sleeping in separate bedrooms, that when work was done Toni was hanging out at the office, not wanting to go home; that she had opened a new email account under the name J. Salvo, and that she had a new bank account shows things were moving forward.”

After Toni s death, authorities received a letter and calls from 16 people requesting they investigate Henthorn s role in Toni s death, as well as the alleged accident in May of 1995 that killed his first wife: Sandra Lynn Henthorn, 37, was crushed by their Jeep Grand Cherokee after it allegedly fell off a jack as she crawled under it to retrieve a lug nut. Henthorn later collected more than $600,000 in life insurance. The Douglas County coroner originally deemed Sandra Lynn s death an accident but has since reopened the investigation.

Sentencing for Henthorn, who could get life in a federal prison without parole as well as a fine of up to $250,000, will take place later.

It won t be the last time in court for Toni s brother. Bertolet tells PEOPLE that the couple’s daughter, Haley, 10, is currently living in Denver with guardians approved by Henthorn. “It is (our) goal to try to adopt Haley or become her permanent guardians down the road. That s our next legal hurdle to jump through,” says Bertolet.

As for his sister, Bertolet says, “We know Toni is in heaven. We are at peace with that. We wanted some justice for what happened to Toni and we didn t want this to happen to anyone else. Obviously Harold viewed women as possessions, not people.”

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