Amid official silence about the motive behind the murders of four Idaho college students, one expert said the evidence is indicating who might have died first in the early hours of Nov. 13.

Bryan Kohberger has been charged with four counts of first-degree murder and felony burglary in the Nov. 13, deaths of Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin.

Joseph Scott Morgan, a distinguished scholar of applied forensics at Jacksonville State University in Alabama, told Fox News that the presence of a tan leather knife sheath in the third-floor bedroom where Goncalves and Mogen had been sleeping that night could speak volumes.

The sheath was mentioned in an affidavit released Thursday. According to it, Moscow Police Department Cpl. Brett Payne found "what appeared to be a tan leather knife sheath laying on the bed next to Mogen's right side."

"I think that’s where the attack initiated, and that’s important. [It] goes to progression, and it goes to who the target was. That was perhaps the specific location he was bound for,” Morgan said.

Morgan offered his opinion on how the sheath arrived where it was found.

"It’s a very dramatic thing when you think about it. He’s near the bed, grabs the handle of the blade and flips that button on the sheath [while] his other hand drops the sheath in the bed after drawing the knife,” he said.

The Idaho State Police lab found Kohberger’s DNA on the button snap of the sheath.

The affidavit also noted that at least one victim may have been awake near the time of the killings, according to The New York Times.

Kernodle, who was on the second floor of the house, received a DoorDash delivery around 4 a.m., which would place the delivery just before a white vehicle identified as Kohberger’s arrived at the house. Kernodle’s phone showed activity at 4:12 a.m.

A survivor of the attack was also awake, according to information contained in the affidavit, according to CBS.

A resident identified as D.M., who also had a bedroom on the second floor, told authorities she woke up around 4 a.m. and heard noises she thought "sounded like Goncalves playing with her dog in one of the upstairs bedrooms, which were located on the third floor," the affidavit said.

"A short time later, D.M. said she heard who she thought was Goncalves say something to the effect of 'there's someone here,'" the affidavit said.

The resident told police that she heard "crying coming from Kernodle's room," and heard a man’s voice saying, "something to the effect of 'it's OK, I'm going to help you,'" the affidavit said.

Later on, she opened her door and "saw a figure clad in black clothing and a mask that covered the person's mouth and nose walking towards her," according to the affidavit.

She told police she saw a man who was "not very muscular, but athletically built with bushy eyebrows."

The man then walked out through a sliding glass door at the back of the house, she said.

This article appeared originally on The Western Journal.