Oregon Man Pushes Girlfriend off Cliff, Assaults Her Underage Sister

In 2009, Stephen Nichols and Rhonda Casto went out for a hike. Hours later, she was found dead and nearly a decade later, Nichols admitted to having sex with her 16-year-old sister.

The 23-year-old Casto and Nichols were parents to 9-month-old Ava. On March 19, 2009, they chose to take a hike on the Eagle Creek Trail along the Columbia River Gorge in Oregon. Later, fire officials got a 911 call from Nichols and found Casto dead. At first, Casto's death was thought to be an accident, but soon police began to suspect murder.

Casto's family was suspicious of Nichols, who denied killing Casto. However, Casto's mother, Julia Simmons, told Maria Elena Salinas in an episode of Investigation Discovery's The Real Story that Casto made a comment before they left that raised eyebrows.

"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,'" Simmons said, reports PEOPLE. "She made a joke of it."

Simmons did not think it was funny at all, so she went straight to the police after hearing about her daughter's death.

"We all told him [the detective] we believe that Steve pushed her. This is not an accident," Simmons said.

Police did not ignore Simmons' theory, but it was not until February 2015 that Nichols was arrested and charged with murder. Prosecutors believed Nichols wanted to collect Casto's $1 million life insurance policy.

Prosecutors also said Nichols had an improper sexual relationship with Casto's 16-year-old sister Melanie. He was also accused of trying to push a previous wife off a balcony in China six years before Casto's death.

"He told Melanie that she was a dead ringer for her sister, and that the baby would forget her mother within just a matter of a short time and that they could be a family - the three of them," Simmons told Salinas, notes The Daily Mail.

During the legal process, prosecutors continued to run into roadblocks. An interview between police and Nichols was not allowed to be used as evidence. Then, prosecutors found that the former detective on the case, who retied in 2012, erased all the evidence he had from his computer.

In May 2017, Nichols agreed to plead guilty to criminally negligent homicide and coercion in exchange for getting the murder charge dropped. He was only sentenced to three years probation and credit for spending 19 months in jail.

Salinas also interviewed Nichols, who maintains his innocence to this day.

"Some people are going to believe I'm innocent and some will believe I'm guilty," Nichols, 42, said. "You can believe whatever you want."

Nichols also said he knew Melanie was underage when they had sex, calling it a "very stupid decision."

As for his version of events from March 19, 2009, Nichols claims he did not remember much from that night, but he said he saw her fall. He claims he tried to help her, but he collapsed on top of her out of exhaustion and hypothermia. Nichols also claims she used marijuana and medication for depression and to lose weight.

According to CBS News, half of Casto's $1 million life insurance policy is in a court-controlled account for Ava. The rest will go to attorneys' fees and Simmons.

Photo Credit: YouTube / Investigation Discovery