MOSCOW, Idaho - EXCLUSIVE: Police initially called the shocking stabbing deaths of four University of Idaho students in their off-campus home an "isolated, targeted" attack, but they've kept most details under wraps as they continue to seek out their suspect.
Kaylee Goncalves, 21; Madison Mogen, 21; Xana Kernodle, 20; and Ethan Chapin, 20, were found dead at a house just yards off campus, hours after police say someone attacked them in their sleep on Nov. 13. The three women lived there, and Chapin was visiting his girlfriend, Kernodle.
Police have kept quiet about crime scene specifics to protect the integrity of their ongoing investigation. However, on Friday, investigators clarified some of their reasoning in an interview with Fox News Digital.
"When the chief said that [the slayings were targeted], and [investigators] still believe that now, it didn't appear that there was any forced entry into the residence," said Aaron Snell, communications director for the Idaho State Police. "There were survivors of this. And then as well, based on the evidence internally at the scene, that has led detectives to believe and continue to believe that this was a targeted event."
He declined to discuss what evidence was recovered inside the scene or to identify whom and how many of the victims specifically the killer was targeting.
In a televised interview, Goncalves' father, Steve Goncalves, reportedly told CNN that he had been informed that there was only one target among the four victims. Separately, he told Fox News last week that the attacker had been "sloppy" and left behind an abundance of evidence.
"The family members, what they say is up to them," Snell said. "The information that we try to release is to the best of our ability, vetted and accurate and correct – and as well, to protect the integrity of the investigation."
He declined to discuss the crime scene details but said he had no qualms about the families speaking out.
"That's totally understandable that he would want to make comments, and that's that's up to him," Snell said. "That's fine."
Whatever the killer's intent was upon entry, the unknown suspect or suspects did not leave until after hacking to death four young people.
Chapin was a member of the Sigma Chi fraternity, majoring in recreation, sport and tourism management, the University of Idaho said. Kernodle and Mogen were both part of the Pi Beta Phi sorority and were marketing majors. Goncalves, a general studies major, belonged to Alpha Phi.
Two of the victims were sleeping on the second floor, and two were on the third, but police have not confirmed whom was found where – or whether the bedroom doors were locked after the slayings.
"We have not released any of that information," Snell said. "We believe that's pertinent to the investigation. There's a lot of questions surrounding that, and we recognize that, and we want to provide that information when we can – but at this point in the investigation, we can't."
Multiple 911 callers alerted authorities around noon on Nov. 13, and officers initially arrived in response to a report of an unconscious person. They found four victims dead inside.
The Latah County coroner later said that all four were victims of homicide by stabbing – and that their wounds had likely been inflicted in their sleep.
Authorities and the property manager have not confirmed whose bedrooms were where. Mogen's boots were visible on the upper-level window alongside a pink letter "M," suggesting that she occupied the third floor.
Goncalves' family told Fox News last week that she and Mogen were very close, like sisters.
WATCH: Parents of Idaho murder victim Kaylee Goncalves speak out
"Maddie was in our oldest daughter's wedding," Kristi Goncavles said. "She said, ‘All of my sisters are my bridesmaids,' and Maddie was one of those bridesmaids, and it was all of Alivea's sisters, including Maddie."
Two roommates, who were asleep on the ground level, were not attacked. Neither was a pet dog in the home.
John Kelly, a criminal profiler and psychotherapist with experience interviewing serial killers, said that due to the lack of publicly available details, he's "up in the air" about whether the attacker was a random stalker or someone familiar with the inside of the home.
But one thing is clear, he said. "He really, really is a savage, with no concern or empathy or anything like that," he told Fox News Digital.
Police and the FBI, who worked through Thanksgiving trying to find answers in murder mystery, are asking anyone with any information on the case – no matter how small – to get in touch.
"We are looking at all angles," Snell said. "Our concept is that if we start getting pigeonholed into a specific idea, we may miss other tips in other pieces of this investigation."
So far, he said, investigators have received more than a thousand tips in the case and are working through them.
"If anybody has information, we're interested," he added. "We believe that what's in a possible video surveillance tape is just as important as what might not be in it, to help us get a clearer picture."
They are also looking into whether Goncalves may have had a stalker – a suggestion that they have so far been unable to corroborate.