Updated

Bryan Kohberger, the 28-year-old criminal justice student accused of killing four undergrads at a neighboring school, arrived at the Latah County Jail Wednesday evening, hours after authorities flew him out of Pennsylvania.

A law enforcement source tells Fox News Kohberger is being held in a separate holding cell and his demeanor "remains quiet."

Police there and the FBI took him into custody on Dec. 30 after raiding his parents’ house in Albrightsville.

Kohberger faces four counts a first-degree murder and a felony burglary charge for allegedly entering a six-bedroom house and stabbing four University of Idaho students.

UNIVERSITY OF IDAHO MURDERS TIMELINE: WHAT WE KNOW

A mug shot head on and side profile of Idaho murder suspect Bryan Kohberger

Bryan Kohberger, 28, is accused of killing Ethan Chapin, Xana Kernodle, Kaylee Goncalves and Madison Mogen. (Latah County Sheriff's Office)

After deputies booked Kohberger into the county jail, his new mugshot appeared on the sheriff's website.

Police identified the victims of the Nov. 13 attack as Kaylee Goncalves and Maddie Mogen, 21, along with 20-year-olds Xana Kernodle and Ethan Chapin, who were dating.

Idaho victims last photo

Ethan Chapin, 20, Xana Kernodle, 20, Madison Mogen, 21, and Kaylee Goncalves, 21, along with the women's two other roommates in Kaylee Goncalves' final Instagram post, shared the day before the slayings. (@kayleegoncalves/Instagram)

After the attacks, Kohberger is believed to have finished the semester at Washington State University, about seven miles away from the crime scene.

He was studying there for a Ph.D in the department of criminal justice and criminology and working as a teaching assistant.

Bryan Kohberger

Bryan Kohberger was stopped by Indiana police Dec 15, 2022, before he was identified as a suspect in the murders of four University of Idaho students. (Hancock County Police Department)

On Dec. 15, the day a Pullman Police SWAT team shot and killed an armed suspect after an hours-long and unrelated standoff, Kohberger was pulled over twice with his father in Indiana, once for speeding and once for tailgating, as they made their way back to the Poconos.

WATCH: New video shows traffic stop in Indiana involving Idaho murder suspect

A source told Fox News' Dan Springer Wednesday that the stops came at the direction of the FBI, who were looking for images of Kohberger's hands.

Kohberger’s Pennsylvania defense attorney said the father’s trip had been planned well in advance.

Bryan Kohberger handcuffed walking on runway

Bryan Kohberger arrives in Pullman, Washington, on his way back to Idaho to face murder charges over four stabbing deaths. (Fox News)

He also said that Kohberger expected to be exonerated in Idaho after waiving his extradition in the Keystone State. 

Kohberger arrived in Idaho just before 6:30 p.m. Wednesday after a cross-country flight from Pennsylvania that made two pits stops along the way.

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Deputies escorted him out of a Pennsylvania State Police plane. He was seen wearing a red prisoner jumpsuit under a heavy jacket.