'He Is Either Going to Give Me a Ring or Throw Me Off a Cliff,' a Mom Allegedly Said Before Fatal Hike

For nearly a decade, mystery has surrounded what happened to 23-year-old aspiring model Rhonda Casto, whose lifeless body was found at the bottom of a steep ravine.

On March 16, 2009, the young mother had set out with her boyfriend, Steve Nichols, to hike the popular Eagle Creek Trail along Oregon’s Columbia River Gorge. But what was supposed to be a leisurely day hike turned into a nightmare when fire officials, responding to a 911 call from Nichols, came across the ghoulish scene of Casto’s death.

What appeared to be an accident turned into a murder investigation, bolstered by Casto’s family’s belief that Nichols — the father of Casto’s daughter, Ava — had something to do with her dying.

Adding to their suspicions was a statement Casto allegedly made before she went on the hike.

“She told my mother and my sister that ‘he is either going to give me a ring or throw me off a cliff, ha ha ha,’ ” Casto’s mother, Julia Simmons, tells reporter Maria Elena Salinas in Monday’s episode of The Real Story with Maria Elena Salinas on Investigation Discovery and exclusively previewed above. “She made a joke of it. ”

But Simmons didn’t think Casto was kidding. And after she died, family members went to the police.

“We all told him [the detective] we believe that Steve pushed her,” Simmons tells Salinas. “This is not an accident.”

Simmons says authorities were very interested in what the family had to say. At the time, however, she says she didn’t confront Nichols with her allegations: “Police wouldn’t let me see him, because they knew I was enraged.”

Rhonda Cast
Rhonda Cast

In February 2015, nearly six years after Casto died, Nichols was arrested and charged with killing her — accused of pushing her off the 100-foot cliff so he could collect a $1-million life insurance policy.

Authorities also pointed to an alleged inappropriate relationship with Casto’s underage sister and a previous incident where Nichols was accused of attempting to push his then-wife off a balcony in China in 2003.

He denied all of these claims and the case encountered multiple legal obstacles as it proceeded.

In February 2017, the Oregon Supreme Court ruled a three-hour police interview with Nichols after his arrest was inadmissible. Adding to the prosecution’s problems was the fact that the former lead detective, who had retired in 2012, destroyed evidence on his computer, including crime scene and autopsy photos and trail-head fee envelopes from potential witnesses.

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In May 2017, in a move that angered Casto’s family, prosecutors dropped the murder charge against Nichols. In return, he pleaded guilty to criminally negligent homicide and coercion.

According to his plea, Nichols received three years’ of probation, with credit for 19 months of jail time.

Nichols still maintains he had nothing to do with Casto’s death. When confronted by Salinas about her alleged prophetic words to her family, he responded: “The simple answer is I don’t think she ever actually said that.”

“She was so happy,” Nichols told PEOPLE in a previous interview about the day the couple went for a hike.

Steve Nichols
Steve Nichols

Though Nichols said he doesn’t remember much about what happened, he did recall Casto running along the narrow trail with a towel over her shoulders, like “Superwoman,” and he said he witnessed her fall.

He tried to help her, he said — sliding down the ravine and trying to swim across a freezing creek to get to her. However, by the time he reached her body, he said, he collapsed on top of her from exhaustion and hypothermia.

Nichols said he believes prescription drugs played a part in Casto’s death, which he called an accident, and he claimed he later discovered she was using marijuana and also taking medication to lose weight and for depression.

But Simmons doesn’t buy Nichols’ story and described her daughter’s relationship with him as volatile, though he said they “hardly ever fought.”

Simmons says Casto was considering ending things with him before she died.

“She was going to move out, but she was trying to get up the courage to do it,” Simmons previously told PEOPLE. “She was worried about not having enough money to support Ava.”

The Real Story with Maria Elena Salinas airs Monday (10 p.m. ET) on Investigation Discovery.