(NEWSNATION) — The probable cause affidavit released Thursday laid out in meticulous detail how authorities linked 28-year-old suspect Bryan Kohberger to the Nov. 13 deaths of four University of Idaho students, but many questions remain unanswered.

The arrest document did not explain why the suspect allegedly committed the crime, nor did it state if there was a connection between Kohberger and the four victims.

Here’s what we still don’t know.

The suspect’s motive

While it offered a detailed account of the steps authorities took to identify Kohberger, Thursday’s affidavit (which can be read in full here) revealed little about the suspect’s motive.

Early in the investigation, NewsNation reported that one of the victims, Kaylee Goncalves, suffered “significantly more brutal” injuries than her best friend Madison Mogen, who was found in the same room.

That detail led many to believe Goncalves was the target of the attack ,but it’s still unclear whether she, or any of the victims, were specifically targeted.

One piece of information the affidavit did offer was that Kohberger — a 28-year-old criminal justice graduate student — posted a Reddit survey asking participants to provide information in order to “understand how emotions and psychological traits influence decision-making when committing a crime,” according to the affidavit.

But at this point, any hypothesis directly linking the killings to Kohberger’s studies is speculation.

The coroner also determined that there was no sign of sexual assault.

Whether Kohberger knew the victims

We don’t know if any of the victims were targeted and we don’t know if the alleged killer knew any of them prior to the attack.

We do know that Kohberger’s phone was in the area around the crime scene “on at least twelve occasions” prior to Nov. 13, 2022, according to the arrest document.

Authorities said all of those occasions, except for one, occurred in the late evening and early morning hours of their respective days.

In one instance, on August 21, 2022, Kohberger’s phone was near the Moscow, Idaho, residence from 10:34 p.m. to 11:35 p.m., according to the affidavit.

It’s possible the suspect’s previous visits to the neighborhood were done as a way to stake out the area before the attack, the affidavit says.

“I also know that on numerous occasions, subjects will surveil an area where they intend to commit a crime prior to the date of the crime,” investigators wrote. “Depending on the circumstances, this could be done a few days before or for several months prior to the commission of a crime.”

Why roommate waited to call police

Perhaps the most shocking piece of information to come out of the affidavit was that a surviving roommate told investigators she saw the alleged killer before returning to her room and locking the door without calling police.

After hearing multiple voices in the house around 4 a.m., as well as someone crying, the roommate 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 investigators.

The man then walked past her as she stood in a “frozen shock phase,” the affidavit says. The witness described the figure as “5’10” or taller, male, not very muscular, but athletically built with bushy eyebrows.”

The roommate then locked herself in her room.

The first 911 call was placed around seven and a half hours later at 11:58 a.m.

“On November 13th, the surviving roommates summoned friends to the residence because they believed one of the second-floor victims had passed out and was not waking up,” Moscow police said. “At 11:58 a.m., a 911 call requested aid for an unconscious person. The call was made from one of the surviving roommates’ cell phones inside the residence.”

Many people have been quick to criticize the response of the surviving roommate but experts say that’s unfair, given the circumstances.

“A state of shock can take hours, days, weeks sometimes to wear off, and so that very well may have been the case,” said former FBI agent Tracy Walder. “It’s really hard to put yourself in a situation like that.”

Mental health professionals agreed.

“A lot of people will say, ‘Well I would react this way or that way,’ but no one really knows until they’re in the situation,” said psychiatrist Dr. Daniel Bober. “I don’t think we can judge too harshly here.”

The surviving roommate’s eyewitness testimony may end up proving vital to the case. When authorities arrested Kohberger, they determined that he matched the description provided by the witness.

What happened to the murder weapon

Authorities have not recovered the weapon used in the killings but that may not be necessary for a conviction.

Investigators were able to link Kohberger to the crime scene due to a “single source of male DNA left on the button snap” of a “tan leather knife sheath” that was found next to Mogen on the bed where she and Goncalves were discovered, according to the affidavit

The words “Ka-bar” and “USMC” were stamped on the sheath, along with the U.S. Marine Corps insignia, authorities said.

Additional questions: Is there other evidence?

The probable cause affidavit shows what led investigators to Kohberger, but that doesn’t mean it’s all the evidence they have.

Authorities laid out how they discovered DNA on the knife sheath and how they believe it was tied to Kohberger, but experts say investigators will be able to determine if his DNA is a direct match with the DNA on the sheath.

It’s also unclear what additional evidence has been collected from Kohberger’s white Hyundai Elantra that’s been recovered by investigators.

Whose footprint was identified?

Investigators detected a shoe print showing “a diamond-shaped pattern (similar to the pattern of a Vans type shoe sole)” just outside the surviving roommate’s door, according to the affidavit. The affidavit did not say if that print has been connected to Kohberger.

Did the second surviving roommate see or hear anything?

A second surviving roommate, whose room was located on the first floor, made statements to investigators that indicated occupants of the house were home by 2:00 a.m. on Nov. 13.

Authorities didn’t say whether that roommate was asleep at the time of the killings — which authorities believe occurred between 4 a.m. and 4:25 a.m. — or if she heard anything suspicious.

(Information from NewsNationNow.com and the Nexstar Media Wire)