The suspect behind the unsolved murders of four University of Idaho students earlier this month was likely someone who knew the victims or a stalker who was familiar with their habits, one of the nation’s foremost criminal profilers hypothesized on Tuesday. 

Tuesday marked nine days since the co-eds were discovered stabbed to death inside their Moscow, Idaho, home. As of Sunday, local, state and federal law enforcement had received at least 646 tips in the week since the Nov. 13 attack, but are still searching for the person or people behind the bloody attack. 

Jim Clemente, a retired FBI supervisory special agent and criminal behavioral analysis expert, told Fox News Digital he believed the suspect was likely a young man who has not carried out such violent crimes before. 

"He’s sloppy," Clemente said, when reached by phone on Tuesday. "This is probably more of a compulsive kind of person, that would put him at a younger age and, maybe in the age group or just above the victims."

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"I don’t think he’s particularly sophisticated, criminally sophisticated or forensically sophisticated," he added. 

The killer’s decision to commit such a brazen crime was indicative of his relationship with one or more of the victims, Clemente hypothesized.

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"Going into an occupied dwelling with six people in … different rooms in the middle of the night is an extremely high-risk crime, unless he knows one or more of the people," the former New York City prosecutor said. "So, that is my first thought on it: this offender did not just randomly choose this location, that he targeted one or more of the people in there. Now, that could be because he has a relationship or a past relationship with one or more of them. Or it could be that he's been stalking one or more of them."

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Asked later about the suspicion that the killer knew his victims, Clemente explained that the offender entered a home in the middle of the night "when anybody living there could have had a gun, multiple people could confront and attack him when he got in."

"Unless he knew them, unless he knew one or more of them," he went on. "I think that reduces the risk if he did, or if he was stalking them, and he knew that on the weekends they all got wasted. And they went to bed early, or they went to bed in the early morning, and they didn't get up till late afternoon because they were all wasted."

He added: "So, if he knew their routine and knew that they were all drunk, then that again reduces the risk to the offender, so making this a more plausible crime to commit. So just the fact that he got away with it in that time."

When asked why he believed the suspect was a male, Clemente pointed to the defensive wounds that some of the victims allegedly had. 

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"They fought back. This is somebody that was able to kill more people, including a male victim," Clemente said. He also referenced the use of a knife as a murder weapon and said, such violence is "more indicative of a male offender." 

He said the time of the attack – during the late-night, early-morning hours – shows "that he has the freedom of movement during that time."

"He’s not in a relationship or a job that would keep him" from committing the crimes during that time, Clemente said. 

Moscow Police received a call shortly before noon on Nov. 13 for a report of an "unconscious person" at the King Road home. Several other people had gathered at the address by the time police arrived, officials said.

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The victims were slain in the second and third floors of their home between 3 a.m. and 4 a.m. on Nov. 13, after they spent the night out. 

The victims were identified as Ethan Chapin, 20, of Conway, Washington; Madison Mogen, 21, of Coeur d'Alene, Idaho; Xana Kernodle, 20, of Avondale, Arizona; and Kaylee Goncalves, 21, of Rathdrum, Idaho.

Two other roommates were inside the home, on the bottom floor, at the time of the murders, but were uninjured. 

The victims are all believed to have been asleep when they were attacked, though some showed signs of defensive wounds. Each victim was stabbed several times, and showed no signs that they were sexually assaulted. They are all believed to have been killed using a single knife.

Clemente, who spent over two decades with the FBI, said it was "important" to note that the killer "chose a knife." 

"Why did he choose a knife? It’s quiet. It didn’t wake up the rest of the residents in the house," he said. "It could be for that reason."

WARNING: THE FOLLOWING IMAGE IS GRAPHIC

But Clemente said it could also be that the offender "is known to carry a knife," and "might even show it off to his friends."

"The fact that he used a knife," Clemente explained. "It’s graphic but we call it, he doesn’t mind wet work – he doesn’t mind getting his hands dirty. He doesn’t pale at the sign of blood."

He said he believed this could mean that the suspect is a hunter, a butcher or is otherwise in a field of that nature. 

"He killed four different people this way. He didn’t just sort of blanch and run after the first one," Clemente said. 

Examining the killer’s behavior before and after the crimes – their pre- and post-offense behavior – can be useful for the community and investigators working to solve the crime, Clemente said, 

Pre-offense behavior includes factors such as that the killer could have been "proud of his knife, and carried it around and showed it off to people." Also, that he "had some kind of contact" with, or was fixated on, one or more of the people in the house. 

As for his post-offense behavior, the suspect would have likely fled the area and "won’t come back until it calms down," Clemente said. At a time when so many people are leaving town for the holiday, such an absence might not be noticeable. 

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"But he may be local, and he may not have shown up for work or was late afterwards," Clemente added. "And he probably has a very significant interest in following the news of this crime."

Moscow Police Department officials are asking the public to share "all outside surveillance video taken from 3 a.m. to 6 a.m. on Sunday November 13, 2022, from businesses and residences within" a specific area. A map of the area in question is below.

A manhunt continues for the person or people involved in the attack. Police are asking anyone with information or footage related to the slayings to call 208-883-7180 or tipline@ci.moscow.id.us.