Accused University of Idaho killer Bryan Kohberger slid into one victim’s direct messages on Instagram just weeks before the four students were killed in their beds, a report said Tuesday.

An Instagram account that belonged to Kohberger repeatedly sent messages to one of the college students found dead — but she never returned his advances, an investigator close to the case told People.

“He slid into one of the girls’ DMs several times but she didn’t respond,” the anonymous source said. “Basically, it was just him saying, ‘Hey, how are you?’ But he did it again and again.”

The messages were reportedly sent in October.

University of Idaho students Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin were found stabbed to death in their off-campus house on Nov. 13.

The source did not disclose which of the girls Kohberger messaged. The suspect followed accounts for all three girls on the social media platform.

The messages from Kohberger’s account were sent around the same time that detectives claim the suspect was stalking the victims. His cellphone data pinged in the same location as the four students in the weeks before the murders.

Kohberger — who was pursuing a doctorate in criminology at Washington State University, 10 miles from the University of Idaho — has been charged with four counts of first-degree murder and a count of felony burglary in the gruesome quadruple homicide.

Authorities aren’t completely sure why the victim didn’t respond to Kohberger’s repeated messages but said it could be simply because she hadn’t noticed them.

“She may not have seen them, because they went into message requests,” the source said, implying that the victim didn’t follow Kohberger back on Instagram. “We’re still trying to determine how aware the victims were of his existence.”

It is not yet clear if the girl’s unresponsiveness was a motive for murder, the source said.

“There’s no indication that he was getting frustrated with her lack of response,” the source said. “But he was definitely persistent.”

Kohberger’s unyielding attempts to reach his alleged victim could be a symptom of the “incel complex” from which a former FBI investigator believes he suffers.

“The murders may have been … an effort to assert some type of dominance,” security expert Pete Yachmetz told The Post this week.

“I believe a continued stabbing of a victim indicates … an uncontrollable rage and extreme anger … I think he may have developed a sort of incel complex.”

A preliminary status hearing for Kohberger has been set for June 26.