FARMINGTON — A man who stabbed a woman and pushed her to her death on Interstate 15 is now suspected of threatening a man with a knife shortly before the murder, according to new charging documents.

The Salt Lake County District Attorney’s Office on Jan. 5 filed a third-degree felony aggravated assault charge against Oscar Cuevas-Landa, 20, of West Valley City. A police probable cause statement said Cuevas-Landa on Aug. 16, 2020, was approached by a man in Murray who thought he may need help.

Cuevas-Landa pulled a knife and threatened the man, the affidavit said. Shortly after, Cuevas-Landa was seen interacting with Shilo Marie Stewart, 34, of Fruit Heights. Police said that as Stewart drove north on I-15 through Farmington, Landa stabbed her repeatedly and pushed her out of the vehicle, into traffic.

Second District Judge Michael Edwards on Jan. 10 sentenced Cuevas-Landa to 15 years to life in prison for first-degree murder in Stewart’s death. He pleaded guilty in September.

Cuevas-Landa was arrested in Farmington, shirtless, bloody and missing a shoe. He told police he had taken LSD and smoked marijuana, the arrest affidavit said.

Cuevas-Landa told police Stewart “looked at him wrong” and he pulled a knife and stabbed her multiple times, the affidavit said. Cuevas-Landa then unbuckled her seat belt and pushed her out of the vehicle, the charging documents said.

An autopsy revealed that Stewart died from sharp force trauma caused by the knife and blunt force trauma to her head caused by falling from the moving vehicle, according to the affidavit.

Cuevas-Landa’s public defender, Ronald Fujino, told Edwards in November that the defendant might withdraw his guilty plea. Fujino said a psychologist’s newly received report included statements attributed to Cuevas-Landa, such as, “I assumed she wanted to kill me and had a gun. … I was too scared and paranoid. … I honestly thought she was going to shoot me.”

But no plea withdrawal motion was filed and the sentencing went on as scheduled.

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