STROUDSBURG, Pa. -- Three days after the arrest of a suspect in the fatal stabbing of four University of Idaho students, authorities have yet to release key details in the case, from whether the suspect knew the victims to what his alleged motive might have been and what finally prompted his arrest.
The arrest of Bryan Christopher Kohberger, 28, came almost seven weeks after Kaylee Goncalves, 21; Madison Mogen, 21; Xana Kernodle, 20; and Ethan Chapin, 20, were found dead November 13 in an off-campus home.
The killings shook the college town of Moscow, Idaho, which hadn't seen a murder in seven years, as some in the community grew frustrated with the limited information authorities shared as their investigation developed.
That was partly due to state law, which limits what information authorities can release before the suspect makes an initial appearance in court, Moscow Police Chief James Fry said Friday, the day authorities announced Kohberger's arrest in his home state of Pennsylvania.
WATCH: Bryan Kohberger arrives at Pennsylvania courthouse
And the probable cause affidavit -- the legal document used to justify Kohberger's arrest and obtain a warrant -- remains sealed until he is returned to Idaho, where he faces four counts of first-degree murder as well as a felony burglary charge, per Latah County, Idaho, prosecutors.
That document, "will tell us an awful lot," said CNN legal analyst and criminal defense attorney Joey Jackson. "It will speak to the issue of probable cause -- why is he under arrest, what is the justification for holding him and for going after him from a prosecution perspective."
Kohberger appeared in court in Pennsylvania Tuesday, where he waived extradition to Idaho, signing the waiver at the defense table with shackles on his wrists. The judge ordered Kohberger be put in the custody of the Latah County District Attorney's Office within 10 days.
Arrangements were being made to transfer Kohberger to Idaho, according to Pennsylvania State Police, but no timeline has been announced.
Until then, here are a few of the key details that remain unknown.
The suspect's relationship to the victims
Authorities have not said publicly whether Kohberger knew any of the victims, who all were found dead hours after a Saturday night out: Chapin and Kernodle had attended a party on campus earlier that night, police have said, while Mogen and Goncalves went to a downtown bar before ordering food at a late-night food truck.
Kohberger lived in the area, Fry indicated Friday: He was a PhD student in the criminal justice program at Washington State University's campus in Pullman, about a 15-minute drive west of Moscow.
Kohberger was a graduate student at the school, Washington State University confirmed in a statement last week, adding the school's police department helped Idaho law enforcement execute search warrants at Kohberger's campus apartment and his office.
There also was law enforcement activity Friday at a Pullman apartment complex where graduate students live, a CNN team observed.
Investigators focused on Kohberger as a suspect, in part, after his DNA was matched to genetic material recovered at the home where the students were slain, two law enforcement sources briefed on the investigation have said.
Genetic genealogy techniques were used to connect Kohberger to unidentified DNA evidence, a source with knowledge of the case told CNN. The DNA was run through a public database to find potential family member matches, and subsequent investigative work by law enforcement led to his identification as the suspect, the source said.
Information about Kohberger's DNA and any prior relationship with the victims are both key pieces of evidence, Jackson told CNN on Monday.
"No. 1: I'm looking for DNA," he said. "Was his DNA (in the residence)? ... Is there any reason to explain the DNA, is there a basis to know or understand why he would be there?"
"Which leads me to No. 2," Jackson said: "Is there any pre-existing relationship? Did he know them? If so, how?"
Families of the victims and law enforcement are going to "go back and look and see if there's any connections between any of the victims and this defendant in this case," Shannon Gray, an attorney for Kaylee Goncalves' family, told CNN Monday.
"And we're going to be providing a list of any connections that we think are important to the Moscow police," Gray said.
"We would encourage the community to send any leads or information to the Moscow Police Department regarding any contacts or any information they may have about the defendant and any of the victims in the case," the attorney said.
The suspect's alleged motive
Investigators also have yet to give any indication of why Kohberger allegedly carried out the stabbings.
In the days since his arrest, there has been a heavy focus Kohberger's study of criminal justice and criminology as a Washington State University student -- a detail a former senior FBI profiler called "very interesting."
"We have had other cases where offenders have been in areas of study that more or less prepare them to commit a crime," Mary Ellen O'Toole told CNN on Sunday. If he is guilty, Kohberger's "area of study is not a result of cause and effect," she stressed, noting studying the criminal mind did not "cause him to do this."
"He's interested in this, but the ideation of committing a violent crime had to already be there in order to motivate him to commit the crime," O'Toole said. "So, this was kind of a conduit to explore what he was already interested in doing."
Kohberger was previously an undergraduate and graduate student at DeSales University, a Catholic university in Pennsylvania, according to a statement from the school. He graduated with a bachelor's degree in 2020 and this year completed his "graduate studies for the Master of Arts in criminal justice program," according to a university spokesperson.
In a post removed from Reddit after his arrest was announced, a student investigator associated with a DeSales University study named Bryan Kohberger sought participation in a research project "to understand how emotions and psychological traits influence decision-making when committing a crime."
"In particular," it read, "this study seeks to understand the story behind your most recent criminal offense, with an emphasis on your thoughts and feelings throughout your experience."
Last month, Kohberger finished his first semester as a PhD student at Washington State University, the school confirmed.
How the suspect stayed free for 7 weeks
It's also unclear why Kohberger wasn't arrested until more than six weeks after the victims were found dead. Fry would not reveal Saturday when Kohberger came onto law enforcement's radar, saying details in the case would be released in time.
Kohberger went home to Pennsylvania for the holidays, public defender Jason LaBar told CNN on Saturday, adding the suspect and his father -- who accompanied his son on the cross-country drive -- arrived around December 17.
A white Hyundai Elantra authorities had been looking for in connection with the killings was found at Kohberger's parents' house, LaBar, the chief public defender for Monroe County, Pennsylvania, confirmed.
The suspect drove the car to his parents' house, according to another law enforcement source, who told CNN, "Sometime right before Christmas we were zeroing in on him being in or going to Pennsylvania."
An FBI surveillance team from the Philadelphia field office had been tracking him for four days in the area where he was arrested, according to two law enforcement sources briefed on the investigation.
While Kohberger was being watched, investigators from the Moscow Police Department, the Idaho State Police homicide bureau and the FBI worked with prosecutors to develop sufficient probable cause to get the warrant. Once the arrest warrant was issued, the Pennsylvania State Police and the FBI made the arrest.
Steve Goncalves, Kaylee's father, said the family was asleep when Gray delivered the news of the arrest.
"I was very excited, because it was a celebration of life -- the same day that we were doing that event," he told CNN's Bianna Golodryga. Goncalves said his wife "wanted to have this event behind us ideally before the event started so she could just focus on our girls, and that's what happened."
"We're definitely going to look at this guy, look him in his eyes. He's going to have to deal with us," said Goncalves, who plans to attend the suspect's court appearances. "He hasn't been dealing with us for seven weeks, it's not about to end."
Authorities continue to ask the public for information. Within an hour of announcing the arrest, Fry told CNN, authorities got roughly 400 calls.
"We want information on that individual," Fry said Saturday. "We want that updated information so that we can start building that picture now. Every tip matters."
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