Bryan Kohberger was a “creepy” loner who went from being “perpetually exhausted” to eerily “chattier” after his alleged slaughter of four Idaho college students, chilling new details reveal.

Kohberger, 28, was arrested Friday in his hometown of Albrightsville, Pa., almost seven weeks after University of Idaho students Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin were found stabbed to death in their off-campus home in Moscow, Idaho.

Since his arrest, former friends, acquaintances and neighbors have stepped forward to paint a disturbing picture of the alleged murderous sicko.

Here’s what we know about Kohberger so far:

A teenage transformation

Kohberger grew up in the Poconos with his parents and sister — and underwent radical changes during his later teenage years.

At Pleasant Valley High School, the suspect was known as an awkward “creep” and “outcast” who repelled girls and reportedly struggled with a heroin addiction.

“I was in the same grade as Bryan,” Deja Mann, now 27, told The Post. “He didn’t have many friends.

“If he tried to flirt with a girl or anything, they’d get a weird feeling in their stomach. I had that feeling towards him, too,” she said. “My instinct was creeper vibes, and I tried to keep my distance from him.”

Mann said she was helped in class by Kohberger’s mother, a paraprofessional, who “never spoke about Bryan.

“I feel so sorry for her and Bryan’s family right now, they didn’t deserve this,” Mann said.

Kohberger had been extremely overweight when he started school, former classmates noted. Then when he returned to school for his senior year, he was rail-thin.

“I remember seeing him and thinking it was a new student. He was so heavy, and he lost so much weight, he almost looked sickly or like it was an obsession,” Dominique Clark, who attended elementary and high school with Kohberger, told The Post. 

When Kohberger had been overweight, he was bullied. But after the weight loss, he went from victim to aggressor, they said.

“There were a lot of bullies at Pleasant Valley in general, and a lot of people were bullied,” said former student Ashley Korkmaz, who was two years ahead of Kohberger in school, to The Post.

“Bryan just wanted to fit in with the popular kids,” said Korkmaz, 29.

“I don’t want to say he was weird, but he didn’t have any social skills and didn’t know how to make friends. … He was just awkward.”

In a series of videos posted after Kohberger’s arrest, former student Casey Amtz described the suspect as a “heavy heroin user back in high school” — a claim repeated to Fox News by a different classmate.

But by 2017, he was sober, Amtz said.

“It was nice to see him clean up,” she noted, adding that he said he was working security detail at a school at the time.

At some point more recently, Kohberger returned to his old high school to work as a part-time security guard.

His criminal-justice background

Kohberger earned a psychology degree from Northampton Community College in 2018.

In 2022, he received a master of arts in criminal justice from DeSales University in Center Valley, Pa. After his arrest, the university said it is “devastated by this senseless tragedy,” while a former professor didn’t hold back her praise of her now-infamous ex-pupil. 

“He was one of my best students ever,” said Michelle Bolger, 33, an associate professor at DeSales. 

Bolger said she was “shocked as s–t” by Kohberger’s bust.

“In my 10 years of teaching, I’ve only recommended two students to a Ph.D. program, and he was one of them,” she said.

After DeSales, Kohberger moved west in August to get his Ph.D in the Department of Criminal Justice and Criminology at Washington State University Pullman.

A loner who didn’t sleep

Although he appeared to have a budding career in criminology, Kohberger also seemed to be an anti-social student who kept strange hours.

“It seemed like he never slept because he was always doing something all night,” said his downstairs neighbor in school-provided housing.

“He’s normally a very late-night person, going to the bathroom and vacuuming at 1 … in the morning,” the resident told The Post.

The neighbor, who asked to remain anonymous, said Kohberger was almost always alone. Once, she could hear a woman in his apartment through the walls, but said that was a rare occasion.

One of his classmates also noticed Kohberger didn’t seem to sleep.

“I did notice he was showing up to class a little late sometimes, he always had a coffee in hand, he always seemed to be just perpetually exhausted,” said Benjamin Roberts, a fellow grad student at Washington State University in Pullman, to NewsNation.

“Bryan seemed like he was on the knife’s edge between exhaustion and worn out, and at the time, it was extremely difficult to tell which was which,” Roberts said.

The classmate described the suspect as awkward and egotistical.

“He had to make absolutely sure you knew he was smart, he had this intellectual capacity,” Roberts said.

Roberts also noticed a now-haunting shift after the Nov. 13 murder: “He did seem to get a little chattier going into the later parts of the term.”

But there was at least one now-momentous moment after the murders during which Kohberger was quiet, another classmate observed. 

Student BK Norton told The Post that when the quadruple murder was brought up in class, Kohberger remained “quiet and deadpan.”

“I don’t believe he had any reaction,” Norton said of Kohberger. “We had quite a long conversation in class about it, too. I don’t believe I remember him commenting about it at all.” 

Creepy vibes outside of school, too

A brewery owner in Pennsylvania said the accused murderer would harass women at his bar.

Kohberger usually sat alone “observing and watching” other patrons at the Seven Sirens Brewing Company — until he started drinking, owner Jordan Serulneck, 34, told NBC News.

His behavior caused enough concern for staff to put a note in the company system about him.

“Staff put in there: ‘Hey, this guy makes creepy comments, keep an eye on him.’ He’ll have two or three beers and then just get a little too comfortable,” Serulneck said.

Kohberger would ask female staff and customers who they were with and where they lived, the owner said. If the women weren’t interested, “he would get upset with them a little bit.”

Seruneck said he was forced to confront Kohberger after he called an employee a “bitch” when she didn’t respond to his creepy questions.

“I went up to him, and I said, ‘Hey Bryan … I just wanted to talk to you real quick and make sure that you’re going to be respectful this time and we’re not going to have any issues,’” the owner recounted. “He was shocked that I was saying that, and he said, ‘I don’t know what you’re talking about. You totally have me confused.’” 

Kohberger never went back to the bar after that, according to the owner.

A supportive family … mostly

Kohberger’s closest kin have stood by him even as he stands accused of such heinous crimes.

“We have fully cooperated with law enforcement agencies in an attempt to seek the truth and promote his presumption of innocence rather than judge unknown facts and make erroneous assumptions,” his family said in a statement released Sunday.

Kohberger seemed to be close with his father, who flew to Spokane, Wash., in December — after the Nov. 13 slayings — and met up with his son before they drove more than 2,500 miles together back to Pennsylvania.

The only other family member who has spoken about him is his former aunt who divorced out of the family. She said he has “very very weird” eating habits.

“It was above and beyond being vegan,” said the aunt, who declined to be identified.

“His aunt and uncle had to buy new pots and pans because he would not eat from anything that had ever had meat cooked in them. He seemed very OCD [obsessive-compulsive disorder].”

Kohberger is likely to plead not guilty in the quadruple slay case, according to his court-appointed lawyer.