Henderson said Baum became enraged when he found the teens smoking marijuana with her at their home in Mammoth, Utah.
Morgan Lewis, who was known as Morgan Henderson at the time of the murders two years ago, testified for three hours on the stand.
‘I told you you couldn’t have guy friends,’ Henderson recalled Baum telling her on the night of December 30, 2017.
Henderson thought the couple had left, and was surprised when Baum calmed down and pulled a fleece jacket and thin black gloves from her wardrobe.
‘His anger completely turned off, and he was charming,’ Henderson recalled.
But then Baum led her outside, where she saw the two teens tied up in the back of Riley’s Jeep.
‘Jerrod told me to get in the car, and I felt I was scared,’ Henderson said, according to Fox 13 Now.
‘And, I listened to him. I knew that something bad was happening. It wasn’t a normal situation.’
Baum drove the couple and Henderson to an abandoned mine shaft known as Tintic Standard No. 2, near Eureka.

‘I thought I was going to die,’ Henderson told the Provo 4th District Court, according to Desert News.
Henderson said Braum led the group through snow and sagebrush. She recalled Otteson telling Braum she was pregnant and allergic to the sagebrush.

The teen asked if he could untie her hands, which were going numb.
‘No,’ Baum replied. ‘We’re almost there.’
Baum then stopped the group in front of the 1,800-foot open mine shaft.
‘I realized even if we listened, it wasn’t going to end well,’ Henderson told the court.
Henderson said Baum then forced her and Otteson to their knees in an ‘execution style’ pose and made Powell stand in front of them.

‘It felt like we were an audience,’ Henderson recalled, according to the Salt Lake Tribune.
Otteson began to whimper and cry and Powell asked Baum if he could kiss her. Baum refused.
Henderson thought Baum then began hitting the teen. It was only when she heard Powell cry out ‘I’m dying!’ that she realized Baum was actually stabbing the teen over and over again.
After Powell fell to the ground, Henderson said Baum waved at the teen and said ‘Goodbye Riley, you piece of s**t’.
Powell had been stabbed several times and his throat had been cut, an autopsy report later found.
Henderson said Otteson continued to cry and promised Baum she wouldn’t tell anyone about what she had witnessed.
Baum held Otteson in his arms and told her ‘It’s okay, darling’, Henderson recalled.
Henderson then felt something warm on her leg and realized it was Otteson’s blood – Baum had slit the young girl’s throat, she said.

Baum appeared in court on Wednesday (pictured) for Henderson’s testimony during his preliminary hearing

Powell and Otteson’s bodies were discovered 100-feet down abandoned mine shaft known as Tintic Standard No 2 (pictured), near Eureka

‘There was so much blood,’ she added.
Henderson testified that Baum then dumped Powell’s body down the open mine before throwing Otteson’s body over as well. They both fell onto a ledge 100 feet down the shaft.
‘Like lambs to the slaughter, they didn’t even fight,’ Henderson said Baum told her.

Baum then began trying to cover up the blood with dirt and told Henderson to stop crying.
‘He looked manic. He looked high. He looked overjoyed,’ she continued. ‘He said the next time I start crying about stupid Riley, I need to think about my little boy and whether I want him to grow up.’
Henderson said Baum bleached and burned their clothes, hid the knife he used in an oil barrel, and put Powell’s keys in random piles of dirt. He also hid the teen’s Jeep.
Authorities questioned the couple after discovering a Facebook message in which Powell agreed to come to Henderson’s home with Otteson the night before the couple disappeared.

Henderson [left] said she witnessed boyfriend Jerrod Baum [right], first kill 18-year-old Riley Powell, repeatedly stabbing him, before he slit Otteson’s throat and dumped both of their bodies in the shaft 

Henderson told police the teens had visited her, but that she didn’t know what happened to them afterwards.
Meanwhile, she became consumed with guilt over the murders as the months went on and Otteson and Powell’s families continued to search for them.
Fearing that Baum would hurt her son if she confessed, Henderson said she decided to get high on psychedelic mushrooms and kill herself in the mountains.
‘I had tremendous guilt, I felt responsible,’ Henderson said.
Authorities stopped her for speeding on the way and discovered an ax, rifle, and knives in her car. That’s when Henderson decided to confess.
‘I wanted those families to have closure,’ she said. ‘I wanted them to know what happened.’

She led police to the teen’s bodies and, hours later, Baum was arrested.
He was charged with aggravated murder, aggravated kidnapping, desecration of a dead human body, witness tampering, and obstruction of justice.

The teens families grieve their death after the bodies were recovered

It would be months before Henderson told police what happened. She first concocted a plan to kill herself because she was consumed by guilt over what she had witnessed, she said.
She took a plea deal in October. She pleaded guilty to felony obstruction of justice and agreed to testify in exchange for no prison time.
She will be released from jail after Baum’s case is resolved.
Baum faces eight charges in the deaths of Breezy and Riley, including aggravated murder and aggravated kidnapping.
Baum appeared in court on Wednesday. He has not yet entered a plea but his defense team fought hard against Henderson’s testimony.
They brought up Henderson’s schizoaffective disorder, bipolar disorder, and depression, questioning whether she could tell the difference from what was a hallucination and what was reality.
Baum’s attorneys also questioned if Henderson’s memory could be affected by the shock therapy she has received for depression, as well as her use of psychoactive mushrooms.

If he is convicted, Baum could face the death penalty

They noted that Henderson had claimed Otteson and Powell’s hands were tied in the front. The teens hands were both bound behind their backs, according to the autopsies.
Following testimony, a judge will determine if there is enough evidence for Baum to stand trial.
Baum’s preliminary hearing will continue on Thursday.
If he is convicted, Baum could face the death penalty.