(NewsNation) — Years before he was fired from his job as a teaching assistant at Washington State University, accused Idaho killer Bryan Kohberger struggled in social interactions in his job as a fish cutter at a lake, according to his former boss.

Charles Conklin, owner of the Big Brown Fish & Pay Lakes, told NewsNation that Kohberger was hired as a seasonal employee to work at the lake in Effort, Pennsylvania, in 2011 when Kohberger was in high school. Part of the job included fileting fish for customers, whom Kohberger struggled to interact with, Conklin said.

“He wasn’t able to make eye contact with customers and be friendly to them,” Conklin said Wednesday on “CUOMO.”

Prosecutors allege that Kohberger is the man responsible for the deaths of four University of Idaho students who were killed in November. They were found dead inside their off-campus rental house, all with stab wounds.

Kohberger was arrested roughly six weeks later and charged with murder. A hearing in the case is set for late June.

In his job at the lake in 2011, Kohberger was tasked with fileting fish, among other duties. Conklin told People magazine that he “never warmed up and got friendly.”

“He was withdrawn and didn’t show improvement,” Conklin added.

Retired FBI agent Jennifer Coffindaffer says that familiarization with a knife could be important for understanding the crime.

“As an investigator, you’re looking at not only why did they commit a crime, but how did they commit a crime and their weapon of choice,” Coffindaffer said. “Why not manual strangulation or using a ligature or even blunt force trauma? But no, he chose a knife, and when I saw this on this application, I thought, ‘Wow, he has at least a familiarization with knives, comfortable enough to seek employment using one.'”

Records obtained by Coffindaffer and provided to NewsNation also show that Kohberger worked as a security guard for the Pleasant Valley School District in Pennsylvania. That’s the state in which Kohberger grew up and where he was arrested at his parents’ home.

“I think that’s really important because we’ve known he was booksmart, but now we know he’s had practical application thereof,” Coffindaffer said.

NewsNation previously reported that Kohberger was fired his from job as a teaching assistant at WSU, the college he attended just miles from the University of Idaho. According to a termination letter, Kohberger had two “altercations” with a professor and didn’t meet expectations as a T.A.