Idaho Teen Is Found Brutally Stabbed To Death In Terrifying Crime Inspired By 'Scream'

It was like a real-life horror movie.

Cassie Jo Stoddart, a beautiful, smart and kind 16-year-old, was found brutally murdered in a relative’s Idaho home where she had been dog-sitting for the weekend.

“There’s a girl dead on my floor,” a woman frantically told a 911 dispatcher on Sunday Sept. 24, 2006 as someone can be heard wailing in the background. “She’s missing a finger.”

Idaho State Police Lt. Robert Rausch rushed to the scene, where he found Stoddart lying on the floor and “lots of blood” everywhere.

The grisly murder shocked the small, quiet town of Pocatello, Idaho, where murders like this just didn’t happen.

But as investigators would discover, the disturbing truth about what happened to Cassie—and who was responsible for her death—would lie in the 16-year-old’s final day alive, according to “Dateline: The Last Day,” streaming now on Peacock.

Cassie was captured on video the Friday morning of Sept. 22 at 8:28 a.m. at Pocatello High School, as she was putting her books into her locker.

The teen was wearing jeans, a green shirt and white jacket as she stopped unpacking her books to briefly say “hi” to the camera.

To her friend, Justin Sands, who sat next to her in English class that Friday, it had seemed like an average day.

“I just remember being in class with her. Yeah, I just remember it was normal day,” Sands said. “If I would have known that was her last day, I would have treated that day different.”

Cassie’s mom, Anna Stoddart, picked up Cassie and her steady boyfriend, Matt Beckham, from school around 3:45 p.m. and dropped both teens off at the relative’s house where Cassie planned to dog sit that weekend around 5:30 p.m.

She checked in with her daughter around 9:30 p.m. and Cassie told her they were just watching movies and she’d call her mom the next day.

“That was the last time that I talked to her,” Anna said.

Just a half an hour later, the electricity in the house went out.

The power outage, although brief, terrified the two teens. Beckham wanted to stay with his girlfriend in the house, but his parents wanted him to come home and picked him up around 11:15 p.m.

It was the last time Cassie was ever seen alive.

Beckham said he tried to call his girlfriend from home around 12:30 a.m. but she never answered.

When her relatives discovered her body on Sunday, Idaho State Police Capt. John Ganske said Cassie had been stabbed “numerous times.”

“From looking at the scene, it was clear that Cassie put up an extreme fight,” he said. “She fought for her life.”

Investigators couldn’t find the knife that had been used to stab her and saw no signs of forced entry. There was also no clear motive, as Cassie had been well-liked at school.

Puzzled by the brief power outage, investigators took fingerprints from the fuse box and found a clear set that matched her mother Anna’s boyfriend. But the man had an alibi for the night of the murder and said his prints were found because he had done some work at the house in the past.

Detectives also took a hard look at Beckham, who had been the last person to see Cassie alive.

“Of course, we had to break the news to Matt that his girlfriend had been murdered and it sticks in my mind that Matt didn’t show a great deal of emotion at all and that was somewhat of a red flag,” Ganske said.

Investigators decided to give Beckham a polygraph test.

Ganske said he passed with “flying colors” but it was what Beckham said in passing that would ultimately break open the case.

Beckham told detectives that on the night Cassie died, two of their friends, Brian Draper and Torey Adamcik, had also briefly been at the house.

The two 16-year-old teens stopped by to hang out around 8:20 p.m. and watched “Kill Bill: Volume 2” before leaving around 9:30 p.m.

The teenagers told detectives they left because they had decided to go to a movie, but curiously neither were able to say what the movie had been about. An employee at the movie theater—who just happened to go to school with both boys—also said with certainty that neither had been at the theater that night.

“They were lying to us. Now, we have to figure out why they were lying to us,” Ganske told “Dateline” reporter Keith Morrison.

When confronted with the lie, Draper admitted they hadn’t been at the movies and said he had been lying because they had really been breaking into cars and he didn’t want to get into trouble.

Investigators set him up to take a polygraph test, but before the test began, Draper got extremely emotional and said he needed to speak to detectives.

As his parents sat in the room with him, Draper recounted how he and Adamcik had gone back to the home that night to turn the power off and try to scare Cassie, wearing masks to disguise their identity. But he claimed he was surprised when Adamcik started stabbing her for real.

“It wasn’t supposed to happen,” he said through tears. “It was supposed to be a joke.”

Draper eventually led detectives to an area near Black Rock Canyon where the two teens had buried evidence from the crime—and it was then that investigators discovered that the murder had been much more sinister than Draper had even let on.

Inspired by horror movies like “Scream,” Draper and Adamcik had decided to create their own real-life version, targeting Cassie for the simple reason that they knew she’d be house-sitting alone.

They had recorded themselves preparing for their chilling mission in a video tape that they had tried to burn. But, investigators were able to recover the footage which captured Cassie’s last day and detailed their plan to take the 16-year-old’s life.

The video tape began with that footage of Cassie at the high school, saying hello to the camera.

The two boys then captured themselves huddled in the high school library, where they made a “death list” of hopeful victims and talked about the plan for that night.

“I’m sorry,” Draper said to the camera. “I’m sorry to Cassie’s family but she had to be the one. We have to stick with the plan.”

The two teens had dropped by the Idaho home that night to get a feel for the home’s layout and unlock a basement door, so they’d be able to secretly sneak back in later.

“Unfortunately, we have the grueling task of killing our friends,” Draper said in the video as the two teens lay in wait in their car not far from the home.

Investigators believe they would have killed Beckham as well, but then he got picked up by his parents, leaving Cassie as their sole victim.

Wearing masks, gloves and carrying hunting knives the pair viciously stabbed their terrified friend to death, after sneaking into the house and cutting off the power once again.

“We’re sick psychopaths who get pleasure out of killing other people,” one of the teens happily said at one point in their video. “We want to be just like ‘Scream.’”

With the treasure trove of evidence buried along the canyon, authorities had all the evidence they needed to convict the two teens of first-degree murder. Both were sentenced in 2007 to life without parole.

More than 15 years after the grisly crime, Draper agreed to talk to Morrison on the phone from the Idaho State Correctional Institution.

“I felt like a nobody and I felt like I’d be somebody if I did something you know, big and bad,” he said now of his reasoning at the time, explaining that he had a stutter as a teen and never felt like he fit in with other kids.

Today, he carries regret “every day” of his life for taking Cassie’s life.

He also message for other kids who feel like outcasts and are considering violence.

“It’s not too late for all the kids out there who are thinking about that stuff now. It’s not too late man to get in engaged in your life and try to improve your life and better your life,” he said.

But it is too late for Cassie.

"Dateline: The Last Day" is available to stream on Peacock, with new episodes dropping Tuesdays.