'Look at the pattern': Former FBI special agent details how officials identified suspect in Idaho slayings

PHILADELPHIA - Officials have made an arrest in the fatal stabbings of four University of Idaho students after a weeks-long search that garnered national attention. 

On November 13, the four students, later identified as Ethan Chapin, 20, Madison Mogen, 21, Xana Kernodle, 20 and Kaylee Goncalves., 21, were found dead in an off-campus rental home in Moscow, Idaho, authorities say. 

Autopsies revealed the four students died after being stabbed and their manner of death was ruled a homicide. 

As the students' murder left the university grieving around the holidays, frustrations grew as weeks went by without a suspect in custody and the community called on police to clarify details. 

Nearly seven weeks after the students were fatally stabbed, 28-year-old Bryan Christopher Kohberger was taken into custody by local police and FBI agents at a home belonging to his parents in Albrightsville, Pennsylvania.

Kohberger has been charged with four counts of first-degree murder and felony burglary, officials say. 

Retired Supervisory Special Agent of the FBI Scott Duffey joined Good Day Philadelphia to discuss the case and how investigators pinpointed Kohberger. 

Duffey says while little information has come from police as the investigation continues, people with knowledge of the case signal that forensic evidence helped investigators find a suspect. 

The Associated Press reported through a source that Kohberger's arrest came after DNA matched genetic material found at the crime scene. 

"That means if we have enough data, we have enough cousins, enough matches, we can eventually narrow it down to just one family and often just one individual," Genetic Genealogist Cece Moore told FOX 29's Chris O'Connell.

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Police received thousands of tips when they announced they were searching for a 2011 - 2013 white Hyundai Elantra that was spotted near the students' home, according to Duffey. 

He says a car of that make and model was discovered at Kohberger's parents' home in Pennsylvania after surveilling the home and the suspect's location. In a television interview, Kohberger's attorney Jason LaBar claimed Bryan and his father were twice pulled over during their 2,500-mile road trip weeks after the alleged murders.

"I don't know whether they were speeding or not or if they were even issued a ticket," LaBar reportedly told NBC. "I just know that they were pulled over in Indiana almost back-to-back. I believe once for speeding and once for falling too closely to a car in front of them."

According to Duffey, agents look for patterns and special characteristics in suspects when working cases like this. 

"You look at the pattern, right? Then you go through all those who have been identified in the prior incidents and there's that social awkwardness, there's that inability to hold down a relationship and law enforcement had done the exact same thing here."  

While no speculation or information has been shared by authorities about a possible motive for the slayings, Duffey believes Kohberger had some connection to the four slain students.

"Motive is important to understand. The motive goes into is it pre-planned. Is this a moment of spontaneity," Duffey said. "I would absolutely have to imagine that he had some connection, whether it's a physical connection that he had been in that house, that he had dated, that he had been to a party."

His ties to Pennsylvania include studies at Northampton Community College and DeSales University and incidents at a local bar. 

According to Jordan Serulneck, a bar owner in Bethlehem, said he knew the suspect only as "Bryan" from when he used to come to the bar while at DeSales University. 

Serulneck says Kohberger threatened female employees and harassed female customers during the times he came to the bar. 

"From what I remember, he was a disrespectful dweeb that we handled swiftly and professionally," Serulneck said in a Facebook post. 

Kohberger appeared before a judge in Monroe County Court on Friday and he is awaiting extradition.