The blood-soaked crime scene where four University of Idaho students were brutally murdered more than one week ago is a "major challenge" for investigators, an expert told Fox News Digital.

"From a blood evidence standpoint, this is a profoundly bloody scene," said Joseph Morgan, distinguished scholar of applied forensics at Jacksonville State University. "It's going to be a very complicated case when you go through blood evidence, when you go to do DNA typing. It's a major challenge." 

Ethan Chapin, 20, Xana Kernodle, 20, Madison Mogen, 21, and Kaylee Goncalves, 21, were stabbed to death Nov. 13 between 3 and 4 a.m. in a rental house near campus in Moscow, Idaho. 

Police believe the victims, who were found on the second and third floors, were ambushed in their sleep.

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The Moscow Police Department has yet to identify a suspect in the horrific crime or determine whether there was more than one assailant.

Each of the students was stabbed multiple times in the chest area, likely by the same weapon, and at least one victim had defensive wounds, according to Latah County Coroner Cathy Mabbutt.

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In stabbing cases, perpetrators often injure themselves, said Joseph Giacolone, an adjunct professor at John Jay College of Criminal Justice and a retired NYPD sergeant. 

"If you're stabbing and hit the bone, the knife kicks back, and your hand gets sliced," he said. 

Morgan added that it could be very difficult to isolate a sample of the killer's DNA if he left one behind. 

"If we believe this is a single killer with a single weapon, the killer is migrating from body to body, and you'll have what's called commingling of blood," Morgan said. "Here's the rub. If this blood is all commingled, it's difficult to distinguish the individual samples." 

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Investigators contacted businesses to see if any had recently sold a fixed-blade knife. One store manager told the Idaho Statesman that police had specifically asked him about a Ka-Bar-style knife.

Morgan was surprised by this detail. "It's a combat knife, single-edged, with a hilt," he said. "It's a short blade, not as robust as other survival knives."

He speculated investigators could have zeroed in on this type of knife because it has a hilt, which may have left bruises around the stab wounds when it was violently thrust into the victims.

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Both Morgan and Giacolone stressed that the investigation is in its early stages, and their analysis of the crime scene is speculative.

Goncalves' parents told Fox News that sifting through the evidence would be a lengthy process based on information they received from police.

"This wasn’t like a pinpoint crime. This person was sloppy," the slain student's father, Steve Goncalves, said. "There's a mess there. And they're gonna have to go through that point by point, and that's going to take a lot of time. That's why they reached out to other facilities to help them with that lab work."

Retired FBI agent Jim Clemente, who now works as a producer for CBS' "Criminal Minds," said another major hurdle for investigators is the mass exodus of students for the Thanksgiving break. Many in the community also fled over fears the killer remained on the loose.

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"This exodus would mask the offender leaving town," he said. "It could also mean that witnesses who saw something relevant are also gone."

The town of 25,000, which had not recorded a single murder in seven years prior to the stabbings, would have fewer surveillance cameras than a larger city, noted Clemente.

As for the killer's attributes, Clemente said he didn't think the attack was random and described the killer as "sloppy and young." 

"It just seems like a targeted event," said Clemente, who is an expert in criminal profiling. "I think it was building up in him for a while, and he just lashed out."

Aaron Snell, Idaho State Police communications director, told Fox News Digital that investigators were probing all leads.

"We have not come to any conclusion yet, and I know that’s frustrating to the public, but this is a very complex and difficult case," he said. 

Anyone with information about the incident is being asked to call Moscow police at 208-883-7054 or email tipline@ci.moscow.id.us.

Audrey Conklin, Emma Colton and Stephanie Pagones contributed to this report.